Simultaneous electric and magnetic two-dimensional tuning of substrate integrated waveguide cavity resonator

A concept of simultaneous electric and magnetic two-dimensional (2-D) tuning of cavity resonator based on substrate integrated waveguide (SIW) technology is presented and demonstrated. For a dominant TE101 mode SIW cavity resonator, magnetic tuning is achieved by loading a YIG ferrite slab and electric tuning is achieved by placing a varactor diode and capacitors in the cavity. Considering only electric tuning using varactor diodes 1.3% of total tuning range is measured, while for simultaneous electric and magnetic tuning it is 7.9% with unloaded Q-factor better than 130. Using 0.05–0.1 pF of surface mount capacitor a total tuning range of 20% is experimentally achieved. Transmission line theory is used to derive a theoretical 2-D tuned resonant frequency curve, which depicts the variation of cavity resonant frequency with external applied magnetic fields and the capacitance values. The designed dual E- and H-field tunable cavity resonator is cost effective and can be applied in frequency-agile microwave systems.