The low frequency tuners are a unique product technology using MPT algorithms for low frequency wideband tuning. Three or more cascaded tuning sections use series transmission cables and parallel rotary capacitors.
The length of the cables and number of tuning sections are optimized for maximum tuning range over a given bandwidth. HLFT tuners use 6 tuning sections allowing second harmonic frequency tuning.
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 O and higher than 0.9 can be obtained using this tuner at all frequency bands.