Issued

This is an up-to-date list of all US Patents issued to Focus Microwaves Inc. Click on the icon for a link to the full document.

  • Transistor Test Fixture with Convex Surface

    Microwave micro-strip or coplanar waveguide (CPW) transistor test fixtures have the top surface of the input and output blocks machined in a convex shape, to allow the soft dielectric substrate to be stretched over the surface and stablish secure and continuous ground contact with the block surface and eliminate spurious cavities and discontinuities.

  • Integrated Split Signal Hybrid Harmonic Tuner

    An integrated hybrid (active-passive) harmonic impedance tuner uses a fixed and an adjustable directional coupler (wave-probe) and a number of independent wideband tuning probes, all mounted  inside the same slabline and housing. The tuning probes are inserted between the fixed and the mobile wave-probes. The fixed wave-probe samples a portion of the forward travelling signal at the fundamental frequency,

    injects it into a power amplifier and the mobile wave-probe adjusts the phase and amplitude of the amplified signal and injects it back into the slabline towards the DUT. The mobile carriages and tuning probes are automated. The mobile wave-probe is either fully or partially (horizontal only) automated or fully manually controlled. Feedback signal phase and amplitude control is obtained through the horizontal and vertical movement of the mobile wave-probe.

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  • Hybrid Harmonic Impedance Tuner

    A hybrid harmonic slide screw tuner uses the forward injection technique, also called Gamma Boosting Unit (GBU) cascaded with two independent tuning probes in the same slabline and housing. The wave-probes used in the GBU sample a portion of the forward travelling signal, adjusts its phase, amplifies it, adjusts its amplitude (attenuation) and couples it back, in reverse direction into the main signal path.

    In the present active tuner technique as is herein implemented, the passive tuners and the signal couplers are mounted on the same double carriages which move each carriage horizontally and the wave- and tuning probes vertically, independently. Appropriate calibration and tuning algorithms ensure independent hybrid (active and passive) harmonic tuning.

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  • Compact Harmonic Amplitude and Phase Controller

    A compact remotely adjustable harmonic microwave attenuator and linear phase shifter (HAPC) is made using two mobile signal couplers (wave-probes) inserted back-to-back in a slabline which is terminated with 50 Ohms. The coupled ports of the wave-probes are connected with the input ports of a power combiner using flexible RF cables and the output port of the combiner is connected to

    the output port of the unit. The new structure allows reducing the required linear length of the slabline by half. The wave-probes are attached to the vertical axes of mobile carriages, which are movable to variable distances from the input port of the HAPC, corresponding to the adjustable transmission phases, whereas the depth, at which the wave-probes are inserted into the slabline, determines the coupling factors and thus the value of the attenuations.

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  • Active Slide Screw Tuner

    An active slide screw tuner uses the forward injection technique, also called Gamma Boosting Unit (GBU) cascaded with a passive impedance tuner in the same slabline and housing. The GBU samples a portion of the forward travelling signal, adjusts its phase, amplifies it, adjusts its amplitude (attenuation) and couples it back, in reverse direction into the main signal path.

    In the present active tuner technique as is herein implemented, the horizontal and vertical movement of the forward coupler through remote control in a tuner-type carriage and vertical axis, eliminates the need of a separated phase shifter and attenuator, which makes the solution better, simpler and more effective.

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  • Hybrid Electro-Mechanical Tuner

    A hybrid electro-mechanical tuner uses a modified version of the forward injection technique, also called Gamma Boosting Unit (GBU), integrated with a passive slide screw impedance tuner in the same slabline and housing. The modified GBU samples a phase- and- amplitude adjustable portion of the forward travelling signal at the fundamental frequency, amplifies it and injects  it back, in

    reverse direction, into the main signal path through a circulator connected at the idle port of the tuner, after the mechanical tuning probe. The horizontal and vertical control of the forward coupler (wave-probe) of the modified GBU which is attached to the vertical axis in a mobile carriage, is manual or remote  and eliminates the need for a dedicated phase shifter and attenuator, making the solution better, simpler and more effective.

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  • High Gamma Compact Harmonic Tuner

    Compact, high Gamma, wideband, multi-carriage-multi-harmonic tuners use a meandering slabline structure and multiple probes and carriages. The meandering structure reduces the overall tuner length by more than half at 0.4 GHz. The required slabline bends are made using a vertical-to-horizontal slabline transition. Multiple probes are employed within the slabline segment closest to the

    test port, in order to minimize the insertion loss at higher frequencies, caused by the slabline bends. This tuner structure is mostly effective starting at fundamental frequencies below 1 GHz and operating at fundamental or harmonic frequencies as high as 18 GHz.

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  • Stable Load Pull Operation Using Tuners

    Load Pull tuning pattern and probe movement algorithms allow creating a test pattern allowing to avoid instability regions and spurious oscillations of microwave transistors during testing using slide screw load and source tuners.

    The impedances are selected based on the stability circle and instability area on the Smith chart and the probe movement trajectory allows both avoiding the static and circumventing the transient crossing through the instability area. All tuning commands are saved in a pattern file.

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  • Transistor Test Fixture with Integrated Couplers and Method

    Microwave transistor test fixtures, both micro-strip and coaxial, include integrated wideband directional signal sensors/couplers and allow the detection of the main signal and its harmonic components, injected into and delivered by a transistor in high power operation mode,

    by using a phase-calibrated network or signal analyzer and allows this way the reproduction of real time signal waveforms. The fixtures are best calibrated using equivalent TRL calibrated fixtures allowing overcoming the incompatibility of the internal ports connecting to the transistor terminals with coaxial cables attached to VNA

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  • Programmable Amplitude and Phase Controller

    A continuously manually or remotely adjustable microwave attenuator and linear phase shifter uses a mobile signal coupler (wave-probe) and a slabline structure terminated with 50 Ohms. The coupled port of the wave-probe is connected with the output port of the unit using flexible RF cable. The wave-probe is attached to the vertical axis of a mobile carriage, which is moved at variable

    distance from the input port, corresponding to the expected transmission phase, whereas the depth, at which the wave-probe is inserted into the slabline, determines the coupling factor and thus the value of the attenuation. Amplifier and low pass filters compensate for coupling loss and equalize for frequency slope.

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  • Method for Reducing Power Requirements in Active Load Pull System

    A method and test setup for reducing the RF power requirement m active load pull uses impedance tuners between the output of the test transistor and the active RF power injection network. The active network uses either a closed loop (active load) configuration or an open loop network employing split or synchronized signal sources.

    The impedance tuners are wideband (fundamental) tuners, harmonic rejection tuners or multi-harmonic tuners. A 7:1 transforming ratio of the tuners represents the best compromise between power matching and tuner loss, yielding a reduction of 11 dB in power requirements from the active load or the synchronized source(s); if only the fundamental signal is injected at the output of the DUT, a multi-harmonic tuner or a harmonic rejection tuner is used for independent harmonic tuning; if multiple harmonic signals are injected, a multi-harmonic tuner is used and creates passive harmonic loads while reducing at the same time the power requirements from the harmonic injection sources.

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  • Compact Multi-Carriage Impedance Tuner and Method

    A new multi-carriage slide screw impedance tuner uses a circular slabline, eccentrically rotating disc probes and rotating carriages allowing reducing the linear size of the tuner by a factor of 3 compared with linear tuners.

    The slabline lies flat on the bench table surface and the disc probes rotate at the end of rotating arms, which act as mobile carriages, forming a planetary configuration. The rotation of the arms control the phase of GAMMA and the rotation of the disc-probes controls its amplitude.

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  • High Frequency Phase Reference Standard Signal

    A pre-characterized high frequency signal (14) is provided by means of a non-linear circuit, for example an amplifier circuit (10), fed with a first signal (12) with a component at a first, fundamental, frequency (FO). The amplifier circuit generates an output signal comprising harmonic components (14h1, 14h2, 14h3) having stable and predetermined phase relation relative to each other.

    Information concerning the phase relation of the harmonic frequency components is provided, for example by means of a data file (16). At least two of the harmonic components are at the tenth or lower harmonic frequencies. The signal strength of such low-order harmonic components may be relative high, thus enabling the provision of a pre-characterized high frequency multi-tone signal from the amplifier circuit with high signal to noise ratio.

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  • Multi-band Low Frequency Impedance Tuner

    A multi-band, electro-mechanical programmable impedance tuner for the frequency range between 10 and 200 MHz uses cascades of three or more continuously variable mechanical capacitors interconnected with sets of low loss flexible or semi-rigid cables; for each frequency band a different set of cables and capacitors are used.

    The cables and/or variable capacitors inside each tuning block are switchable manually or remotely. Multi-section variable capacitors are also used. Instantaneous impedance tuning is effectuated by changing the state of the capacitors using electrical stepper motors. The tuner is calibrated using a vector network analyzer and the data are saved in the memory of the control computer, which then allows tuning to any user defined impedance within the tuning range. Reflection factor values between 0 and higher than 0.9 can be obtained using this tuner at all frequency bands.

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  • High Frequency High Reflection Pre-Matching Tuners with Variable Zero Initialization

    Automatic microwave pre-matching tuners with new zero positioning capability allowing for a minimum idle airline section between pre-matching and tuning section, thus minimizing insertion loss and enhancing high reflection tuning capability at high frequencies and tuner calibration algorithm of the pre-matching section over one half of a wavelength and of the tuning section over one full wavelength at each operation frequency and associated tuning and measurement operation algorithms.

  • High Reliability Power Tuners

    Impedance tuners used in high power measurements suffer fast heating and consequently thermal expansion of the central conductor, which has a very small mass and is thermally isolated from the tuner housing. This leads to false measurements or catastrophic tuner failure (short) of either the DUT or the tuner.

    A method is introduced for allowing the center conductor to expand linearly without deforming and risking loss of accuracy first and catastrophic failure later. Practical tests have shown significant thermal behaviour improvement.

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  • Tuning Method for Hybrid Active Injection Load Pull System

    A harmonic load pull system uses a number of synchronized signal sources to inject harmonic power into the output of a power transistor. The mismatch between the signal sources and the transistor internal impedance is reduced by using multi-harmonic tuners, which pre-match the impedance of the signal sources to the internal impedance of the transistor at each harmonic frequency independently.

    Actual tuning is electronic by changing the amplitude and phase of the injected signals. The transmitted and reflected waves are measured and optimized through bi-directional couplers connected between the transistor and the tuner and a wideband harmonic receiver.

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  • Calibration of High Frequency Signal Measurement Systems

    A method of calibration a high frequency signal measurement system is described. The measurement system is in the form of a network analyzer (6) and has first and second phase locked signal sources (SS1 & SS2) and at least two measurement receivers (18a, 18b). A phase meter (26) is provided.

    A reference signal (F0) is outputted at a first frequency from the first signal source (SS1). The second signal source (SS2) steps through a multiplicity of different test frequencies (nF0), which are applied in turn to part of the measurements receivers (18a, 18b), of characteristics of the resulting signal at a measurement place. The absolute phase of the signal at the measurement plane is also measured with the phase meter (26). Calibration data is generated which relates the characteristics of the signals as measured by the measurement system (6) and the absolute phase as measured with the phase meter (26).

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  • Multi-Frequency Attenuation and Phase Shifters

    A multi-frequency programmable and remotely controllable variable attenuator and phase shifter (MF-VAPS) network utilizes wideband three port circulators, power combiners, high-low pass filters and a calibrated multi-harmonic tuner to control the amplitude and phase of the transmission factor (A21) at up to three user defined frequencies individually.

    The harmonic signal components are divided in frequency bands and injected into the circulator’s port 1 and extracted from port 3, whereas the tuner is connected to port 2 and terminated with Zo. When the tuner is initialized (S11=0) the transmission factor of the network is zero; when the tuner is at maximum reflection at any frequency the transmission factor is also maximum. Changing the reflection phase of the tuner controls the transmission phase <A21 by the same amount, up to 360°.

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  • Multi-band Low Frequency Impedance Tuner

    A multi-band, electro-mechanical programmable impedance tuner for the frequency range between 10 and 200 MHz uses cascades of three or more continuously variable mechanical capacitors interconnected with sets of low loss flexible or semi-rigid cables; for each frequency band a different set of cables and capacitors are used.

    The cables inside each tuning block are switchable manually or remotely. Impedance tuning is possible by changing the state of the capacitors using electrical stepper motors. The tuner is calibrated using a vector network analyzer and the data are saved in the memory of the control computer, which then allows tuning to any user defined impedance within the tuning range. Reflection factor values between 0 and higher than 0.9 can be obtained using this tuner at all frequency bands.

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  • Wideband Slide Screw Impedance Tuner

    Multi octave frequency-range electro-mechanical impedance tuners cover frequencies from the  megahertz (FM range) to the high (millimeter-wave) gigahertz range, by combining a high frequency with one or two low frequency slide screw tuner modules. Special configurations allow for compact size.

    The low frequency module can be bypassed using SPDT remotely controlled millimeter wave switches. Appropriate calibration, control and tuning procedures allow for a fully integrated operation.

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  • Low Cost Probes for Slide Screw Tuners

    A new tuning probe for slide-screw impedance tuners uses a simplified semi-cylindrical tubular form. This ensures reduced manufacturing cost and high machining tolerance for probes using galvanic ground contact. RF performance matches or exceeds traditional cubical probes both using galvanic and capacitive ground contacts.

  • High Power Slide Screw Tuners

    Impedance tuners used in high power measurements suffer fast heating and consequently thermal expansion of the center conductor, which has a very small mass and is thermally isolated from the environment and tuner housing. This leads to false measurements or catastrophic tuner failure (short) of either the DUT or the tuner.

    Modified center conductors are made of two pieces and comprise a flexible joint between them that allows longitudinal center conductor expansion and contraction, thus preserving tuner accuracy and safety. Practical tests have shown significant improvement in thermal behaviour.

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  • High Speed Hybrid Active Load Pull

    A high speed tuning and measuring algorithm is used for production level testing on-wafer a large number of chips. It applies to a hybrid active injection load pull test system. Using a pre-calibration of the passive tuner and the amplitude and phase settings of the active power injection signal and employing fast harmonic receiver VNA

    the test system is capable of executing frequency and time domain load pull measurement sets including more than 50 impedance points in a total of 1 second for quantities such as delivered input and output power, PAE, power gain and other. Overall test time, including device hoping and biasing on the automatic probe station is less than 1.5 seconds. This enables production level load pull operations.

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  • Wafer Probe Holder for Planarity and Orientation Adjustment

    A compact device allows individual or combined correction of wafer probe planarity and orientation misalignment. The device is made as a metallic block or as a strong plastic block and contains three sections, which are held together by a steel blade or by a steel blade and a rotation pin; the sections are split apart for “Phi” – orientation alignment or rotated against each-other for “Theta” planarity alignment.

    The steel blade provides secure and anti-backlash flexibility both in lateral (“Phi”) and perpendicular (“Theta”) direction. Alternatively the “Theta” alignment can use a rotation shaft or a small part of the original block left over as a bridge joining both sections. The device is inserted between the fixed probe support and the probe itself.

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  • Variable Capacitors for High Accuracy Tuning

    Improved interdigital parallel plate rotary capacitors to be used in automatic MHz range tuners have a grounding technique based on bronze sliding contact to effectively and continuously lead to the ground terminal the rotating comb-like blades of the capacitor and (optional) damping resistors inserted between the sliding contact and the ground terminal.

    The resistors reduce the high Q of the series resonance of the capacitor with the fringe lead inductance. Tuning sensitivity is reduced and tuning accuracy and repeatability are increased.

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  • Method for Calibration and Tuning with Impedance Tuners

    An impedance synthesis method for single and multi-probe high resolution slide screw impedance RF and microwave tuners employs a fast calibration algorithm, which creates appropriately distributed calibration points over the Smith chart and a second order interpolation algorithm between calibration points, optimized for best suitability to the natural behavior of the tuners.

    The fast tuning algorithm uses a general search in order to identify the closest calibrated points, followed by a gradient search using fine interpolation grid in order to reach the final target. The method is applicable, after proper data preparation, also to double and triple probe harmonic tuners. The method allows tuning accuracy as high as -60dB, or deviation-from-target vector distance of 0.001 units on the Smith chart, whereas absence of the fine grid interpolation typically yields accuracies of the order of -20 dB, or a deviation-from-target vector distance of 0.1 reflection factor units.

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  • Compact Two Probe Impedance Tuner

    A new slide screw impedance tuner structure uses a circular slabline, eccentrically rotating disc probes and a rotating carriage allowing reducing the linear size of the tuner by a factor of 3. The slabline lies flat on the bench table surface and the disc probe rotates at the end of a rotating arm, which acts as a mobile carriage, forming a planetary configuration.

    The rotation of the arm controls the phase of GAMMA and the rotation of the disc-probe controls its amplitude.

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  • Circular Impedance Tuner

    A new slide screw impedance tuner structure uses a circular slabline, eccentrically rotating disc probes and a rotating carriage allowing reducing the linear size of the tuner by a factor of 3.
    The slabline lies flat on the bench table surface and the disc probe rotates at the end of a rotating arm, which acts as a mobile carriage, forming a planetary configuration.

    The rotation of the arm controls the phase of GAMMA and the rotation of the disc-probe controls its amplitude.

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  • Coaxial Alignment Instrument Adapter

    An adapter alignment device, that can be added on the coaxial RF connectors of instruments, especially slide screw impedance tuners, aligns and guides precisely and repeat ably the male and female adapters into each-other. This leaves the internal center conductors of the tuner slabline,

    which are attached to the connectors and to external manually handled cables, intact; this is crucial for all instruments, most of all electro-mechanical impedance tuners, where data generated by previous calibrations are used in later measurement and where any other type of numeric adapter error correction or error model is impossible.

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  • Noise Parameter Measurement System

    A noise parameter test setup yields accurate four noise parameters (Fmin, Rn, Γopt) of microwave transistors over a wide frequency range by merging the s-parameter (signal) measurement path and the noise measurement path, avoiding the RF switches and improving the measurement accuracy.

    Calibration of the system uses TRL and a similar concept as prior art solutions. Additional power control precautions of the VNA sources are necessary to avoid injecting large signal power into the sensitive noise receiver during s-parameter measurements and jamming the weak noise power during noise measurement.

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  • Hybrid Load Pull System and Method

    Fast tuning and measuring algorithms in open loop active load pull systems have been developed to accommodate high speed production testing of many chips of the same kind on wafer; they are based on re-setting the (pre-calibrated) amplitude and phase of the injected power into the device output port.

    Because of the dispersion of the chip characteristics this often leads to non-physical load synthesis, i.e. |Γ| > 1, which not only is unrealistic test condition, but also risks destroying the device under test, or reflection factors not high enough to reach the optimum Gamma of the DUT. A method is proposed to use a mechanical tuner in order to shift the active tuning inside meaningful areas; the tuner is also used to pre-match the device to the injection amplifier.

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  • Intelligent Mechanical Balancing Apparatus for Slide Screw Tuner

    An intelligent, independent and universal mechanical balancing apparatus for automatic microwave multi-probe slide screw tuners allows stable on-wafer testing of sub-micrometric devices. Low loss rigid airlines (bend-lines) used to connect the multi-probe tuner with the chips, in order to improve the tuning range at the DUT reference plane,

    causes mechanical movements of the wafer probes attached to the rigid bend-lines, when the tuner mobile carriages move horizontally. Stabilizing the center of gravity (balancing) of the tuner by means of exactly controlled counter-weights, driven by the same firmware which controls the tuner motors, allows for synchronized compensation of the probe movement and safe on wafer load pull operation.

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  • A Wideband Attenuation and Phase Controller

    A continuously manually or remotely adjustable microwave attenuator and linear phase shifter is made using a two section slabline structure in which a “U” formed center conductor forms a line –stretcher to adjust the transmission phase and slivers of ferromagnetic material are inserted into the magnetic field of the slabline,

    or thin layers of dielectric material are inserted into the electric field serving either way to reducing the amplitude of the transmission factor, or increase the attenuation. The unit is manually or remotely controlled, in which case its transmission behavior can be calibrated on a VNA and used in test software for automated differential load pull operations.

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  • Noise Parameter Extraction Method

    A wideband four noise parameter extraction method uses randomly distributed source states; the data are collected using wideband electro-mechanical tuners and noise and small signal receivers (network analyzers) in fast frequency sweeps; because of the random nature of source impedances reliable noise parameter values are extracted using selected source admittance states,

    distinctly regrouped in a cluster around the reflection factor associated with the optimum noise figure Fmin and a cluster located anti-diametric to it for determining the equivalent noise resistance Rn. Multiple noise parameter extractions for all possible cross-combinations of source impedance states in each cluster at each measured frequency allows reliable and physically meaningful generation of wideband noise parameters, even for very low noise and potentially unstable DUT’s.

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  • Low Frequency Coaxial Capacitors and Tuners

    A new type of variable coaxial, low frequency capacitor uses two cylindrical blocks, which are interdigitally insertable into each-other to create an adjustable capacitance. Each block is made using a conductive (aluminum, brass or copper) strip which is mounted vertically on a conductive basis and is wound in spiral form around a centre axis.

    The blocks are guided coaxially into each-other and the relative orientation angle allows approaching the surfaces of the conductive strips from a maximum distance, which is half the width of the spiral gap, to full galvanic contact. The block penetration is motor controlled and a cascade of three or four such capacitors and associated lengths of coaxial cable is used to make wideband impedance tuners operating in the low MHz frequency range.

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  • A Method for Planarity Alignment of Waveguide Wafer Probes

    A “theta” angle adjustment method for waveguide probes uses an adjustable solid parallelepiped that allows the wafer probes to be fastened to the auxiliary equipment under correcting “theta” angles and a flange holding and securing bracket that allows one waveguide section to rotate against the other.

    The alignment procedure requires one of both flanges to have its aligning pin holes and fastening screw threads replaced by circular (oval) holes, allowing the waveguide sections to rotate axially against each-other. The Theta angle is adjusted by repeated trial and error fastening and unfastening the securing bracket under firm pressure of the probe body against the solid support parallelepiped.

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  • Gamma Boosting Unit (GBU) for Hybrid Load and Source Pull

    A hybrid load pull tuner system uses a combination of a passive and active tuner system. A closed loop system means that the system is independent of the available power of the device under test (DUT). The proposed hybrid system is formed around a closed loop Gamma Boosting Unit (GBU) consisting of two back to back broadband directional couplers,

    broadband variable time-delay, broadband variable phase-shifter and a broadband microwave amplifier, all inserted in the coupled path of the couplers; the GBU is connected in cascade with a passive tuner and boosts its reflection factor; for this the amplifier must have enough linear power and gain to match the difference between the power reflected back to the DUT by the passive tuner and the desired total reflected power to reach the expected Gamma, considering coupling loss and insertion loss of the test fixture.

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  • An Impedance Tuner with Adjustable Electrical Length

    Single and multi-probe slide screw impedance tuners use a slabline filled with dielectric and the same probe and center conductor as in air. The dielectric filling reduces the overall tuner length by a factor of 1/√εr. The increase in loss, and associated reduction in reflection factor, is partly compensated by the shorter size and travel of the probes.

    A typical length reduction is 40%. Using low loss oil reduces the electric field between probe and center conductor and increases Corona threshold; lubrication of sliding contact between probe and slabline walls and cooling of the center conductor are additional benefits. Probe grounding is established either by adjustable top mounted conductive slabs or spring loaded grounding contact on the probes. The method is most effective for tuners with lowest frequency between 100 and 200 MHz and harmonic tuners with lowest frequency between 200 and 400 MHz.

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  • A Method for Planarity Alignment of Wafer Probes

    A "Theta" angle adjustment tool is made of a solid parallelepiped and adjusting screw, that allows the wafer probes to be fastened to the auxiliary equipment under correcting "Theta" angles. The procedure consists of loosening the probe and pressing hard on the tool to force the probe to adjust to the intended slope ("Theta") and then fastening the probe under pressure against the tool and chuck surface.

    Following that the marks left hen the probe tips touch the wafer are assessed and corrective action is taken regarding "Theta misalignment".

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  • A Load and Source Pull Test System for RF and Baseband Frequencies

    A load pull measurement setup allows independent impedance tuning at RF frequencies at the output of the DUT as well as independent tuning at RF and baseband frequencies of the modulated signal at the input of the DUT. This allows optimizing baseband frequency impedances for nonlinear amplifier performance when processing modulated signal,

    such as IMD, ACPR etc. Baseband tuning is done using a low frequency programmable impedance tuner, which is connected through the input bias tee, which acts as a frequency separator (diplexer). The input bias tee may be an LC based network or a 3dB matched coupler based network.

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  • Impedance Tuners with Rotating Multi-Section Probes

    A new slide-screw impedance tuner structure uses multi-section, disc-shaped, rotating metallic probes. This ensures probes covering multiple frequency bands to be served using a single vertical control mechanism, instead of multiple axes, motors, motor control and double or triple carriages.

    Additional benefits are high resolution in the area where the gap between center conductor and probe is small (high GAMMA), smooth increase of proximity between probe and center conductor (basic anti-corona form) and the possibility to compensate for the negative phase slope at higher GAMMA, native to traditional slide screw tuners.

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  • A Method for Maximizing for Reflection Factor of Impedance Tuners

    An automatic microwave load pull slide screw tuner uses two RF probes, either independently movable or linked together, in order to generate high VSWR; precise alignment of two RF probes inside the same slabline is critical, since they must glide seamlessly inside the slabline slot, very closely to the center conductor over large horizontal displacements;

    a self-alignment mounting joint for the probes is described, which allows one or both of them to be mounted on the tuner’s vertical axis held by a flexible steel blade, which allows sidewise movement and tilting and self-alignment of the probe, but also ensures unyielding movement in vertical and horizontal directions, as required for exact re-positioning of the probe during measurement. In case of double probes mounted on the same tuner axis the steel blade provides for a number of probe spacings, which allow the frequency range of the tuner to be switched for various applications.

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  • Impedance Tuners with Rotating Probes

    A new slide-screw impedance tuner structure uses eccentrically rotating metallic probes. This ensures high resolution in the area where the gap between center conductor and probe is small (high GAMMA), a smooth increase of proximity between probe and center conductor (basic anti-corona form)

    and the possibility to compensate for the negative phase slope at higher GAMMA, native to traditional slide screw tuners. Additionally the new structure simplifies the tuner mechanics by eliminating the need for a precise vertical axis.

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  • Wideband Tuning Probes for Impedance Tuners and Method

    Multi-segment RF probes for automatic slide screw impedance tuners include a multitude of slugs, which are individually adjustable towards the center conductor of the slabline and spaced against each-other in order to create the required capacitance and transmission line space values needed for synthesizing resonant networks to match arbitrary reflection factor patterns over a given frequency range.

    The multi-segment probes are optimized using network synthesis software within the limits of the capacitance and inductance values allowed by the hardware. The probes allow constant phase testing for 100MHz bandwidths or more.

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  • Wideband Attenuation and Phase Controller

    A continuously manually or remotely adjustable microwave attenuator and linear phase shifter is made using a two section slabline structure in which a "U" formed center conductor forms a line -stretcher to adjust the transmission phase and slivers of ferromagnetic material are inserted into the magnetic field of the slabline,

    or thin layers of dielectric material are inserted into the electric field serving either way to reducing the amplitude of the transmission factor, or increase the attenuation. The unit is manually or remotely controlled, in which case its transmission behavior can be calibrated on a VNA and used in test software for automated differential load pull operations.

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  • Multi-Source Active Injection Load Pull System and Method

    A harmonic load pull system uses a number of synchronized signal sources to inject harmonic power into the output of a power transistor. The mismatch between the signal sources and the transistor internal impedance is reduced by using multi-harmonic tuners,

    which pre-match the impedance of the signal sources to the internal impedance of the transistor at each harmonic frequency independently. Actual tuning is electronic by changing the amplitude and phase of the injected signals. The transmitted and reflected waves are measured and optimized through bi-directional couplers connected between the transistor and the tuner and a wideband harmonic receiver.

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  • A Mechanically Short Multi-Carriage Tuner and Method

    Mechanically short multi-carriage impedance tuners use meandering slabline structures. The meandering structure reduces the overall tuner length by a factor of 2.5 at 0.4GHz. The critical issue of slabline bends is addressed with several low loss, low reflection alternatives. A preferred configuration comprises a vertical-horizontal slabline transition.

    Cable connections are discarded because of reflections and insertion loss. Measured results show acceptable performance. The tuner is mostly interesting for relatively lower microwave frequencies, such as 1GHz.

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  • An Impedance Tuner using Dielectrically Filled Airline

    Mechanically short single and multi-carriage impedance tuners use a dielectrically filled slabline. The dielectric filling reduces the overall tuner length by a factor of 1/√εr. The increase in loss, and associated reduction in reflection factor, is partly compensated by the shorter size and travel of the probes.

    A typical length reduction factor is 40%. Using dielectric low loss oil also reduces the electric field between probe and center conductor and increases Corona threshold; lubrication of sliding contact between probe and slabline walls and cooling of the center conductor are additional benefits. The method is most effective for wideband tuners with lowest frequency of operation between 100 and 200 MHz and harmonic tuners with lowest frequency between 200 and 400 MHz.

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  • Waveguide Tuners with Planarity Adjustment for Wafer Probing

    An assembly of electro-mechanical impedance tuner and signal processing unit covering frequencies in the millimeter-wave region (26- 110GHz) uses wafer probes to test chips on wafer with capacity of adjusting the probe tip planarity. The assembly uses flexible waveguide between the tuner test port and the wafer probe port and micrometer adjustment of the planarity angle 8 between the plan of the probe tips and the wafer surface in order to optimize RF and DC contact.

  • Improved Mechanically Controlled Variable Capacitors for Impedance Tuner

    Mechanically short multi-carriage impedance tuners use meandering slabline structures. The meandering structure reduces the overall tuner length by a factor of 2.5 at 0.4GHz. The critical issue of slabline bends is addressed with several low loss, low reflection alternatives.

    A preferred configuration comprises a vertical-horizontal slabline transition. Cable connections are discarded because of reflections and insertion loss. Measured results show acceptable performance. The tuner is mostly interesting for relatively lower microwave frequencies, such as 1GHz.

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  • Method for Preventing Electrical Short in Impedance Tuners Using Mechanical Stop

    Mechanical vertical stops, in form of metallic or plastic screws or dowel pins are introduced as permanent limits and attached on the tuning probes or the vertical axis of slide screw impedances tuners; the vertical stops are adjusted in order to prevent the probes from getting closer to the center conductor than a certain limit;

    this limit is calculated to prevent corona discharge at a specified maximum RF power and a required maximum reflection factor (Gamma). The adjustment method uses measured data of Gamma as a function of the vertical position of the probe to estimate and adjust for the requested gap to be maintained between the probes (at their lowest position) and the center conductor at any given RF power. The technique can be used in automatic, stepper controlled, as well as in manual, micrometer screw controlled, tuners.

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  • Adjustable Signal Sampling Sensor and Method

    Wideband low loss signal couplers use an electric field antenna for voltage detection and a magnetic loop for current detection both placed inside and coupled to the center conductor of a coaxial or parallel plate airline. The signal coupling factor increases with frequency thus favoring detection of harmonic components generated by the nonlinearly operated RF transistors.

    In order to adapt also to various power levels and associated harmonic receiver sensitivity the detectors can be adjusted such as to vary the basic level of coupling. A calibration method allows considering non-infinite directivity of the signal couplers to be accurately considered even when they are terminated with very high VSWR, generated by impedance tuners connected to the signal couplers.

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  • Noise parameter Measurement System and Method

    A wideband four noise parameter measurement system and method uses electro-mechanical wideband tuners and fast noise and small signal receivers (network analyzers) to collect noise data in fast frequency sweeps over a large number of randomly distributed source tuner states;

    because of the random nature of source impedances, additional monitoring equipment allow evaluating critical device parameters in view of output mismatch and instabilities in order to validate the measured data. Multiple noise parameter extractions for all possible cross-combinations of source impedance states at each measured frequency allows reliable and physically meaningful generation of wideband noise parameters, even for very low noise and potentially unstable DUT's.

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  • VHF Harmonic Impedance Tuner

    An impedance synthesis method for fundamental and harmonic frequencies using multi section tuners, because of the huge amount of possible tuning permutations, employs a search strategy based on the minimization of an ERROR FUNCTION (EF), in two steps:

    in a first step a coarse calibration grid is generated and the raw area is found which allows an approximate solution to the tuning task at the fundamental frequency; then a fine impedance grid is generated around the first solution using calibrated and interpolated points at all harmonic frequencies; a second search step, using the same EF, then allows fine tuning. Among the several, numerically found solutions, the most reliable one is selected based on a sensitivity criterion, which calculates the impedance change for a possible small error in repeatability of each tuning element and selects the one with the lowest sensitivity to element setting errors.

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  • Calibration and Tuning Using Compact Multi Frequency-Range Impedance Tuners

    A calibration and impedance synthesis method applies to automatic multi frequency-range electro-mechanical impedance tuner which cover frequencies from a low megahertz to a high gigahertz range; this is possible by cascading a high frequency tuner module with one or two low frequency tuner modules;

    the low frequency module(s) are made using either “variable phase shifter-capacitor” or “multi-capacitor-transmission line tuner” structures. The high frequency module is a single, double or triple probe slide screw tuner, with the individual probes covering adjacent frequency bands. Calibration is measuring S-parameters of each tuner module on a VNA, cascading in memory and saving in cal-files. Tuning employs search routines in calibration data base targeting the closest calibrated point versus a user defined impedance.

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  • VHF Harmonic Impedance Tuner

    An electro-mechanical VHF harmonic load pull tuner is made as a cascade of three independent tuning sections, each including three adjustable shunt air capacitors inter-connected using coaxial cables of appropriate length, or one section of nine shunt capacitors inter-connected using coaxial cables; each capacitor is adjustable to at least 20 values (states);

    the tuner creates independently controllable impedances at three (harmonic) frequencies in the frequency range between 10 and 150 MHz. An Error Function-based optimization algorithm allows impedance tuning at three frequencies independently, by optimized searching among the more than 20.sup.9.apprxeq.512,000,000,000 possible combined tuner states. This allows matching the output of VHF transistors and amplifiers at the fundamental and harmonic frequencies. Stepper motors, drivers and control software are used to automate, calibrate and use the harmonic tuner in an automated harmonic load pull measuring setup.

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  • Method for Reducing Power Requirements in Active L/P Systems

    A method for reducing the RF power requirement in active load pull systems uses impedance tuners between the test transistor output and the output port of the active system. The active system is either a closed loop (active load) system or an open loop system using split or synchronized signal sources.

    The impedance tuners are wideband (fundamental) tuners, harmonic rejection tuners or multi-harmonic tuners. A 7:1 transforming ratio of the tuners yields a reduction of 11dB in power requirements from the active load or the synchronized source(s); a multi-harmonic tuner or a harmonic rejection tuner is used for independent harmonic tuning, in case of absence of a harmonic injection from the active load; a multi-harmonic tuner is used as a pre-matching section creating harmonic loads and reducing the power requirements from the harmonic injection sources as well.

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  • Impedance Tuner with Integrated Bias Network

    Single and multi-probe slide screw impedance tuners incorporate DC bias networks. The bias networks can be inserted at the test port, between DUT and first tuner probe/slug, or at the idle port, between tuner probe/slug and load or source.

    The bias networks are designed and optimized for different frequency and DC power (current, voltage) ranges and are insertable and exchangeable, depending on the application. The effects are short-circuit protection, higher compactness and shorter supply lines leading to: a) better control of spurious oscillations and IF impedance and b) improved sideband up-mixing behavior of the DUT in modulated-signal nonlinear applications.

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  • Impedance Tuners with Mechanical Stop

    Wideband and multi-section probes (slugs) for slide-screw impedance tuners use means for mechanical limitation of vertical movement towards the center conductor of the slablines, in form of cross bar structures and/or adjustable screws or dowel pins, in order to prevent the probes from having mechanical/galvanic contact with the center conductor of the slabline.

    The limiting screws or dowel pins can be mounted on the probes themselves or on the vertical tuner axis. Fine adjustment allows optimizing the maximum reflection factor at various frequency ranges and probe sizes.

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  • Self-Adjustable Probes for Slide Screw Impedance Tuners

    An automatic slide screw impedance tuner uses one or more adjustable RF probes, either independently movable or linked together, in order to generate high VSWR; precise alignment of two RF probes inside the same slabline is critical, since they must glide seamlessly inside the slabline slot, very closely to the center conductor over large horizontal displacements;

    a self-aligning link between the tuner axis and the probes is made using a flexible steel blade and allows one or both of them to be mounted on the tuner's vertical axis in a manner that allows lateral and tilting self-alignment of the probe with hysteresis-free movement in vertical and horizontal directions, as required for exact re-positioning of the probe in the slabline during measurement. In case of multiple probes mounted on the same tuner axis the steel blade link provides also for variable spacing for optimum frequency operation of the tuner.

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  • Compact Multi Frequency-Range Impedance Tuner

    An automatic multi frequency-range electro-mechanical impedance tuner covers frequencies from a low megahertz to a high gigahertz range, by combining a high frequency with one or two a low frequency tuner modules; the low frequency module is made using either variable phase shifter-capacitor or multi-capacitor-transmission line tuner structures.

    The high frequency module is a single, double or triple probe slide screw tuner covering up to 1.5 decades in frequency; the low frequency tuner is using cascades of three or more capacitor-coax cable tuning sections or a low frequency phase shifter combined with a variable shunt capacitor; the low frequency tuner can operate as low as a few megahertz whereas the high frequency tuner can operate up to several gigahertz. Depending on the application, low frequency parallel-blade capacitors or high frequency coaxial trimmers are used. Typical cross-over frequencies between low and high frequency modules range from 200 to 800 megahertz, lowest frequencies can reach below 10 megahertz and highest frequencies 26 to 40 gigahertz. Appropriate calibration, control and tuning procedures allow for a fully integrated operation.

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  • Harmonic Impedance Tuner with Four Wideband Probes and Methods

    A method for calibrating multi carriage-multi probe impedance tuners for synthesizing distinct, user defined impedances at a number of harmonic frequencies, employs two-port s-parameter characterization of the tuning sections on a pre-calibrated vector network analyzer at a pre-selected number of probe positions.

    All tuner probes are wideband and capable of creating high reflection factor at all harmonic frequencies considered. The data are saved in memory and all permutations of the s-parameters at all harmonic frequencies are generated. Subsequently the data are organized blocks based on reflection factor values fitting in a number of segments of the Smith chart; this allows accelerated numeric search through a pre-selection of data block depending on the target reflection factor chosen. The method can be used for two three and four probe tuners.

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  • Wideband Low Frequency Impedance Tuner

    Compact electro-mechanical impedance tuners for frequencies as low as 1 MHz use the concept of a cylindrical transmission line with the signal conductor being a spiral wire wound around a metallic cylinder and separated from it by a layer of dielectric material.

    A conductive wheel is running over the spiral wire and, as the cylinder rotates, the transmission phase between one terminal of the spiral wire and the wheel changes. By connecting a rotating parallel plate variable capacitor to the wheel creates an impedance tuner, capable of generating high reflection factors at very low frequencies at any area of the Smith chart. By cascading two or more such tuners allows tuning at harmonic frequencies at the rate of one frequency per tuner section. The reduction in size comparing with traditional transmission line tuners is of the order of 150:1.

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  • Wideband I-V Probe and Method

    Low loss current and voltage probes are integrated in parallel plate airlines (slablines) to be used either as separate modules inserted between tuner and DUT in load pull test setups, or integrated in the impedance tuners themselves.

    The probes are inserted orthogonally at exactly the same reference plane relative to the DUT, maximizing bandwidth and the minimizing deformation of the detected electric and magnetic fields. The probes are used to detect the actual voltage and current waveforms and feed into an amplitude-and-phase calibrated high speed oscilloscope, including several harmonic frequencies. The actual real time voltage and current time domain waves are transformed into the frequency domain using fast Fourier transformation (FFT), de-embedded to the DUT reference plane and inverse transformed into the time domain using inverse Fourier transformation (FFT.sup.-1). The result of this real-time operation is the actual dynamic load line of the DUT at its terminals.

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  • Compact Harmonic Impedance Tuner

    An impedance matching, harmonic electromagnetic tuner has an airline with multiple slots to reduce the overall length of the tuner. At least one RF probe is disposed within each slot so that it can be moved parallel to, towards and/or away from a center conductor. Each of the probes may be put in user selectable positions to create a user selectable impedance.

  • Harmonic Rejection Tuner with Adjustable Short Circuited Resonators

    A harmonic rejection tuner, used for reflecting RF power at the harmonic frequencies in a load pull measurement setup, uses adjustable capacitive grounding of half wavelength long resonator stubs in order to vary the electrical length and thus the resonant frequency of the resonators.

    Since the resonators themselves are by nature narrowband, this frequency adjustability allows for a higher frequency bandwidth and better coverage of operational frequency range of the test setup. Since load pull measurements are carried out mostly at fixed frequencies, adjustment of the capacitive shorts can be either manual or by remote control. Capacitive shorting the resonator stubs allows DC bias to be applicable to the device under test through the tuner.

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  • Impedance Tuners with Resonant Probes

    Slide screw impedance tuners use resonant probes in order to avoid uncontrollable reflection factors at harmonic frequencies in high power load pull transistor testing. The tuners use either coaxial slotted airlines or slablines.

    The probes are coupled capacitively with the central conductor of the airline and are either slotted with associated spring loaded effect for better galvanic ground contact, or solid dielectrically coated or anodized and carefully machined for slide fitting into the slabline opening or the coaxial line slot, for capacitive contact with the ground plane. The probes allow for selective reflection behavior over a given frequency range, which does not include unwanted frequencies, such as harmonic or sub-harmonic frequencies.

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  • Wideband Low Frequency Impedance Tuner

    An electro-mechanical impedance tuner generates wideband and complete Smith chart reflection factor coverage at frequencies as low as 1 MHz. It comprises an in-line adjustable linear phase shifter and a variable capacitor connected in parallel to ground.

    The transmission line, which serves as an adjustable phase shifter of variable electrical length, is made as a cylindrical rotating spiral wire-over-ground transmission line, on which runs a sliding contact, connected with a variable capacitor; the capacitor can be, depending on the frequency, immersed in a dielectric liquid, such as oil (.di-elect cons..sub.r.apprxeq.3) or alcohol (.di-elect cons..sub.r.apprxeq.20) for increased capacitance. The cylindrical structure of the spiral transmission line allows for a compact, 1 meter long apparatus at 1 MHz, whereas the required linear electrical length for this type of impedance tuner would be 150 meters in air, or 100 meters when low cost polyethylene dielectric (.di-elect cons..sub.r.apprxeq.2.25) is used. Cascading two or more tuners allows pre-matching and harmonic tuning.

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  • Harmonic Impedance Tuner with Four Wideband Peobes and Method

    A slide screw microwave impedance tuner has four independent carriages, which slide across a low loss slabline. Each carriage has one or two vertical axes and associated stepper motors and gear, allowing the precise positioning of RF probes (slugs) into the slot of the slabline at any horizontal or vertical position.

    Each RF probe generates wideband reflection when approaching the center conductor. The associated calibration and tuning software can identify combinations of tuner probe positions corresponding to reflection factors such as to create independent tuning at up to four different frequencies. In case of harmonic frequencies the coverage of the RF probes has to be at least two octaves, i.e.: maximum: minimum frequency .gtoreq.4:1; in practice frequency coverage is higher than 4:1, since most applications require a certain operation bandwidth; in the typical case of a fundamental frequency band of 1.8-2.5 GHz the frequency range covered by the RF probes needs to be 1.8 to 10 GHz, the maximum frequency being 42.5 GHz=10 GHz.

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  • Autonomous Impedance Tuner with Human Control Interface

    An electro-mechanical microwave impedance tuner operates as a stand-alone instrument and includes on-board digital processor, firmware, memory, digital display and human control interface, in form of a joystick, mouse, keyboard or tactile (touch sensitive) screen in order to recognize and execute commands for moving the tuner motors and probes,

    generating required microwaves impedances and calculating losses and de-embedding to reference planes different than the tuner ports. Before being used in operations the tuner can also be controlled by a control computer in order to be calibrated on a network analyzer and the data can be uploaded into the on-board memory in order to be used in the above calculations. During measurement and tuning operations the tuner is therefore stand-alone and totally independent of a control computer.

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  • Compact Harmonic Impedance Tuner

    Compact high reflection and harmonic frequency impedance tuners use the slide screw principle and new slabline structures, either with three slots arranged at 120.degree. to each other or four slots arranged in a cross form 90.degree. to each other.

    The tuners comprise up to three and up to four mobile carriages correspondingly, which slide horizontally across the length of the slabline(s), each carriage holding one or two stepper motors and one or two conductive RF probes, which can be inserted into the corresponding slots of the slabline(s) and create adjustable reflection factors through capacitive coupling with the center conductor of the slabline(s). The length of the tuners is considerably reduced, since the probes share the same sections of slabline. The tuners can be used for wideband, high reflection and multi-frequency (harmonic) tuning.

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  • High Frequency Circuit Analyser

    An analyzer for measuring the response of an electronic device (DUT 206) to an RF input signal from a signal generator (240a) is described. An active load pull circuit (201) is connected to the DUT 206, which receives an output signal from the DUT 206 and then feeds a modified signal back to the DUT 206.

    The signal is modified by a signal processing circuit (237) in view of input signals x, y to control the magnitude gain and phase change effected by the feedback circuit (237). Thus, positive feedback loops are avoided and better control of the analyzer is permitted. A network analyzer, or other signal measuring device (242), logs the waveforms (from which s-parameters derived) observed at ports of the DUT 206, thereby allowing the behavior of the DUT 206 under various load conditions to be analyzed.

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  • Low Frequency Harmonic Load Pull Tuner and Method

    An electro-mechanical harmonic load pull tuner uses three variable and adjustable shunt air capacitors and three variable and adjustable series phase shifters and creates independently controllable impedances at three harmonic frequencies in the frequency range between 30 and 250 MHz.

    Independent harmonic tuning is possible because the combination of adjustable shunt capacitors and series phase shifters allows generating more than 10.sup.19 impedance states at each frequency covering the entire Smith chart; appropriate impedance-search Error Function-based optimization algorithms allow fast harmonic tuning for impedance tuning and matching the output of RF transistors and amplifiers at the fundamental and harmonic frequencies. Stepper motors, drivers and control software are used to automate, calibrate and use the harmonic tuner in an automated harmonic load pull measuring setup.

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  • Low Frequency Electro-Mechanical Impedance Tuner

    A segmented, electro-mechanical, remotely controlled programmable impedance tuner for the frequency range between 10 and 200 MHz uses a cascade of three continuously variable mechanical capacitors interconnected by a set of two low loss flexible or semi-rigid cables;

    the electrical length of the interconnecting cables between the capacitors determines the frequency at which tuning coverage of the entire area of the Smith chart is optimum; for maximum impedance coverage the length is to be chosen such as to generate a transmission phase shift of 60 degrees at the center frequency between each capacitor stage. Remote tuning is possible by changing the value of the capacitors using electrical stepper motors. The tuner is calibrated using a vector network analyzer and the data are saved in the memory of the control computer, which then allows tuning to any user defined impedance within the tuning range. Reflection factor values between 0 and higher than 0.9 can be obtained using this tuner.

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  • Harmonic Rejection Tuner with Adjustable Resonators

    A harmonic rejection tuner, used for reflecting RF power at the harmonic frequencies in a load pull measurement setup, uses adjustable capacitive loading of open quarter wavelength long resonator stubs in order to vary the electrical length and thus the resonant frequency of the resonators.

    Since the resonators themselves are by nature narrowband, this frequency adjustability allows for a higher frequency bandwidth and better coverage of operational frequency range of the test setup. Since load pull measurements are carried out mostly at fixed frequencies, adjustment of the capacitive loading can be either manual or by remote control. Capacitive loading the resonator stubs allows DC bias to be applicable to the device under test through the tuner.

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  • Harmonic Load Pull Tuner with Resonant Pre-matching Module

    A harmonic rejection load pull tuner uses a resonant pre-matching module in order to enhance the reflection factor (tuning range) at the fundamental frequency without affecting the tuning range at the harmonic frequencies.

    The insertion loss of the harmonic tuner itself, if such a pre-matching module is not used, reduces the tuning range, generated by a wideband tuner at the fundamental frequency, connected after the harmonic tuner. In order to re-establish and increase the tuning range of the fundamental tuner a resonant pre-matching module is used, which increases the tuning range at the fundamental frequency and has no effect on the harmonic impedances. A wideband pre-matching module is not useful, since while it increases the tuning range at the fundamental frequency, it limits the tuning range at the harmonic frequencies.

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  • Method of Combining Signals and Device Therefor

    A bias T device (20) and a method for combining a first DC signal with a second RF signal is disclosed. The device (20) is provided with a first signal splitting means (30) in the form of a hybrid 90 degree (quadrature) coupler having at least two isolated transmission lines (34,40).

    The first signal splitting means (30) is adapted to receive said first signal at one input (22) and said second signal at another input (24). A second signal splitting means (32) having at least two isolated transmission lines (34', 40') is also provided. Said second signal splitting means (32) is coupled to said first signal splitting means (30) such that the respective sets of transmission lines (34, 34', 40, 40') comprise isolated signal routes (70, 72) through said device (20). An output (26) provides an output signal comprising a combination of said first DC signal and said second RF signal. A coupling effect between at least two of said transmission lines (34, 34', 40, 40') is used to combine said first signal with said second signal.

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  • Frequency Selective Load Pull Tuner and Method

    An automatic, frequency selective microwave tuner, used for load pull transistor testing, is capable of generating independently controllable reflection factors, both in amplitude and phase, at several, harmonic or not, frequencies simultaneously.

    The tuner employs horizontally and vertically adjustable high Q resonant probes and replaces, when used in harmonic load pull set-ups, otherwise required combinations of wide-band tuners with harmonic rejection tuners or wide-band tuners and frequency discriminators (diplexers or triplexers).

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  • Triple Probe Automatic Slide Screw Load Pull Tuner and Method

    An automatic, electromechanical microwave tuner, used for load pull transistor testing, employs three horizontally and vertically adjustable RF probes; the tuner creates very low mechanical vibrations, because it is capable of generating all microwave reflection factors required for complete load pull and noise measurement operations, using only vertical probe movement; it also provides high tuning dynamic range, large frequency bandwidth and continuous choice of tuning target areas.

  • Mechanically Balanced Microwave Load Pull Tuner

    A mechanically balanced automatic microwave tuner is described for use in on-wafer device testing. Using low loss rigid airlines to connect the tuner and the devices causes mechanical movements of the wafer probes, when the tuner mobile carriage moves horizontally. Balancing the tuner by means of exactly positioned and dimensioned mobile counterweights, driven by the same mechanism as the tuner carriage itself, allows for compensation of the probe movement and safe on wafer testing.

  • High Reflection Microwave Tuner Using Metal-dielectric Probe and Method

    An automatic electro-mechanical microwave tuner to be used in transistor load pull and noise testing, comprises a horizontal slotted airline with a test and an idle port and two horizontally remotely movable metal-dielectric combination probes, used to generate very high reflection factors at the tuner test port over a wide frequency range.

    The probes are square metallic slugs as wide as the slot of the airline and of various lengths and include encapsulated dielectric cylindrical inserts of various diameters, which slide on the central conductor of the slotted airline; the mutual horizontal distance between the probes determines the amplitude of the reflection factor and their common distance from the tuner test port determines its phase. A tuner calibration method consists of an algorithm, which measures S-parameters of the tuner two-port as a function of the probe positions and saves those in calibration data files for later use.

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  • High Frequency, High Reflection Pre-Matching Tuners with Variable Zero Initialization

    Automatic microwave pre-matching tuners with new zero positioning capability allowing for a minimum idle airline section between pre-matching and tuning section, thus minimizing insertion loss and enhancing high reflection tuning capability at high frequencies and tuner calibration algorithm of the pre-matching section over one half of a wavelength and of the tuning section over one full wavelength at each operation frequency and associated tuning and measurement operation algorithms.

  • Low Loss Integration of Wafer Probes with Microwave Tuners

    This invention relates to the reduction of insertion losses and by consequence maximization of reflection factors for on-wafer load pull testing of high power or low noise transistor chips, using as much a direct integration as possible between the slotted airline of the tuners and low loss probes, said probes being either modified commercial probes or probes made as an extension of the tuner slotted airline itself.

  • Microwave Tuners for Wideband High Reflection Applications

    High reflection load pull tuners are proposed, which include two or more RF probes, placed in series into the same slotted airline (slabline) and being controlled simultaneously horizontally and vertically by remote electric control, allowing the creation of controlled reflection factors which are distributed over and cover the entire Smith Chart, from very low reflection factors up to very high reflection factors and a method allowing to align such tuners and to calibrate such tuners on a vector network analyzer.

  • Adaptable Pre-Matched Tuner System and Method

    The present invention is an adaptable pre-matched tuner system and calibration method for measuring reflection factors above .GAMMA.=0.85 for a DUT. The system includes a first and second large-band microwave tuners connected in series, the first and second large-band tuners being mechanically and electronically integrated; and a controller for controlling the two large-band tuners.

    The first tuner is adapted to act as a pre-matching tuner and the second tuner is adapted to investigate an area of a Smith Chart that is difficult to characterise with a single tuner, so that the combination of the first and second large-band tuners permits the measurement of reflection factors above Г=0.85. The pre-matched tuner system allows the generation of a very high reflection factor at any point of the reflection factor plane (Smith Chart). The pre-matched tuner must be properly calibrated, such as to be able to concentrate the search for optimum performance of the DUT in the exact location of the reflection factor plane where the DUT performs best, using a pre-search algorithm.

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  • Methods and Apparatus for Time-Domain Measurement with a High Frequency Circuit Analyzer

    A method of measuring the response of an electronic device to a high frequency input signal is performed with an analyzer (1). The method includes providing an electronic device (for example a transistor or amplifier) to be tested, providing a measurement system (10, 11a, 11b, 12, SA, SB) including a microwave transition analyzer (MTA) (10) connected to the device,

    applying a signal to the device and measuring with the MTA (10) the resulting incident and reflected waves at a port (3, 4) of the device, ascertaining first calibration data regarding the measurement system (10, 11a, 11b, 12, SA, SB), processing signals representative of the waves as measured by the MTA (10), with the use of the first calibration data, to compensate for the influence of the measurement system and the connection between the MTA (10) and the device on the waves between the port (3, 4) of the device and the MTA to produce vector corrected s-parameters, ascertaining, by measuring signals at a port of the device with a real network with known properties, second calibration data concerning voltage waveforms at the port, and processing said vectors corrected s-parameters with the use of the second calibration data to produce output signals from with the absolute values of the magnitude and phase of waves at the port of the device may be directly ascertained. The method is of use in improving the efficiency and power capabilities of amplifiers for use in mobile communication base stations.

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  • Low-Loss Microwave Device Test Fixture with Adjustable Blocks

    The present invention relates to a low-loss microwave device test fixture which presents as little losses as possible along the signal path and which can permit impedance transformations. The test fixture includes a frame having two opposite extremities, a top, a bottom, a height and a width.

    The device is further provided with a device supporting column located between the two extremities, having a top surface lying below the top of the frame adapted to receive the device. Two adjustable blocks are further provided, each located between the device supporting column and an opposite extremity, each of the blocks being vertically adjustable. Between the adjustable blocks and the top of the device are two brackets, each for receiving a flange of a device, each of the brackets being secured to an opposite extremity of the frame. The device can be secured to the column and the column and the blocks can be vertically adjusted. The vertical adjustment permits the impedance transformation, and air is used as a dielectric to minimise the losses along the signal path.

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  • Harmonic Rejection Load Tuner

    The present invention discloses a harmonic rejection load pull tuner. The tuner of the invention has a large-band tuner having an input and an output, and a transmission line having a longitudinal axis. The transmission line has an input connected to the output of a DUT and an output connected to the input of the large-band tuner.

    In parallel with the transmission line is at least one stub, the at least one stub having a length adapted to reflect out an nth order harmonic of a base frequency, where n is an integer greater than 1. The tuner of the present invention can be used to perform input or output characterisation (or both) of a DUT, by selectively reflecting out at least one harmonic frequency of the base frequency. Consequently, the characterisation of the DUT is improved, since the effects of the harmonics are considerably reduced. The present invention also concerns a method for performing input or output characterisation.

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