Electrically tunable substrate integrated waveguide reflective cavity resonator

This paper presents a novel electronically tunable substrate integrated waveguide (SIW) cavity resonator at microwave frequency. The resonant frequency of the cavity is tuned with different DC biasing voltages applied over a varactor coupled to the cavity. This structure has been analyzed with a full-wave software package. To validate our analysis, an X-band reflective tunable SIW cavity resonator is designed and fabricated as an experimental example. Measured results show that the tuning range of the resonator is about 160 MHz with loaded Q_L of 150. The proposed resonator can be used to design tunable devices such as microwave and millimeter-wave voltage controlled oscillator (VCO).