Transparent Band-to-Band Frequency Reconfigurable Microwave Absorber using Vanadium Dioxide based Switchable Ground Plane

Vanadium dioxide (VO
2
) is a phase change material that manifests a reversible insulator to metal transition at $\sim 68^{\circ}\mathrm{C}$. VO
2
proclaims more than three orders of resistance switching, low on state resistance and fast transition (ns), which has encouraged its substantial application in RF switching, and reconfigurable microwave devices. This simulation work reports a transparent band-to-band frequency reconfigurable absorber using VO
2
based switchable ground plane between the top layer and bottom optically transparent ITO metallic ground plane. In insulating state of VO
2
, incident waves are transmitted through the switchable ground plane and proposed absorber resonates in the C-band from 5.71 GHz to 8.84 GHz with the reflection coefficient of $\sim -28$ dB at 6.84 GHz. Whereas, in the metallic state of VO
2
, switchable ground plane acts as a reflector. As a result, the absorber operates in the X and Ku bands from 10.28 GHz to 21.7 GHz with $\sim -26$ dB reflection coefficient at 15.23 GHz. The metallic ITO layer at the bottom serves as a ground plane as well as a heater to thermally trigger the phase transition of the VO
2
film.