High-power impedance tuner utilising substrate-integrated evanescent-mode cavity technology and external linear actuators

A 100 W electronically controlled impedance tuner is introduced and experimentally investigated here. The proposed tuner is composed of two individually controlled coupled evanescent-mode (EVA) cavity resonators implemented on a printed circuit board (PCB) using substrate-integrated waveguide (SIW) technology. The contactless tuning mechanism relies on two high-resolution external linear actuators controlling the gap size of each resonator with submicron accuracy. A 3.3 GHz prototype tuner successfully handled up to 100 W of input power with similar to 90% Smith chart coverage at the centre frequency and about 52% bandwidth demonstrating at least 50% coverage. Exhibiting low loss of 0.56 dB and very high stability as well, the proposed impedance tuner is a viable solution for high-power applications where electronic precise tuning is desired.