Frequency agility of dielectric resonator using top‐loaded rotatable anisotropic metasurface

Dielectric resonators (DRs) are widely investigated and applied due to the high Q‐factor feature. Their frequency agility is desperately needed in modern communication systems. In this letter, we propose a novel tuning method for DRs using top‐loaded rotatable anisotropic metasurface, instead of the traditional mechanical tuning structures or electrical switches. The effective permittivity of the anisotropic metasurface varies with the E‐field direction of the incident wave. We can tune the resonate frequency by rotating the metasurface placed on the top of the DR. To demonstrate the feasibility of this method, a tunable DR with the anisotropic metasurface printed on a thin substrate is designed, fabricated, and measured. With a compact profile, the prototype provides a wide tuning range of 8.4% from 4.80 to 5.22 GHz and a Q‐factor higher than 1098. The good tuning performance makes the proposed method highly potential for tunable filters and frequency‐reconfigurable antennas.