A Design of a Impedance Tuner With Programmable Characteristic for RF Amplifiers

This letter presents the quantitative analysis of a novel reflection type electronic impedance tuner. The proposed impedance tuner consists of a 3-dB 90° coupler, variable phase shifter, and attenuator. A 180° variable phase shifter with constant insertion loss and wide variation range low phase shifting attenuator was used to independently control the magnitude and phase of the proposed impedance tuner. Due to independent controls of phase and magnitude, the proposed impedance tuner has a programmable characteristic. The fabricated impedance tuner shows a uniform impedance distribution in polar form with magnitude deviation of less than average 0.24 dB for standing wave ratio $\le 8$ at 2.14 GHz.