Focus has received notice of allowance for one more US patent
VHF HARMONIC IMPEDANCE TUNER
Filed on 12 July 2011
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 150MHz. An Error Function-based optimization algorithm allows impedance tuning at three frequencies independently, by optimized searching among the more than 209 ≈ 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.