Low frequency harmonic load pull tuner and method / 7,646,268

Tuesday, January 12, 2010

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.