Harmonic rejection tuner with adjustable short circuited resonators / 8,362,787

Tuesday, January 29, 2013

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.