A Frequency-Tunable Dielectric Resonator Antenna With Rotatable Anisotropic Metasurface

This letter introduces a frequency-tunable dielectric resonator (DR) antenna (DRA) with a top-loaded rotatable anisotropic metasurface. The metasurface at different angles can be equivalent to materials with different permittivity. As a result, the frequency of the DRA operating at
TM
_δ11
mode can be continuously adjusted. The working mechanism of the proposed tunable DRA is given in detail. Since both the mechanical tuning scheme and DR are adopted, the proposed design shows high efficiency (low loss) and small size. For demonstration, a differential-feeding prototype is fabricated and measured. The center frequency can be tuned from 6.64 to 6.96 GHz as the metasurface is rotated by 90°. Within it, the radiation pattern is stable, and the radiation efficiency is more than 76%.