Ku Band High-Q Switchable Cavity Filter Using Vanadium Dioxide (VO2) Microwave Disk-Shaped Switch

This paper presents the design, fabrication and measurements of Ku-band high-Q tunable resonator and tunable two-pole filter using Vanadium Dioxide (VO₂) Phase Change Material (PCM) diaphragm. The device consists of a copper surface mounted cavity, bonded on a sapphire substrate, on which are processed the VO₂-based disk-shaped irises. The irises are located opposite to capacitive posts, in the middle of each cavities, where the E-field of the resonant mode is maximum in order to ensure a wide tuning range. Using the reversible Metal-to-Insulator Transition (MIT) of VO₂, the resonant frequency of the resonators is shifted by changing the conductivity of the switches. Electromagnetic simulations have been conducted and exhibits 8% frequency shift from 13.68 GHz to 14.7 GHz and an unloaded quality factor (Q_u) from 1198 to 142.