An Air-Gap-Based Frequency Switching Method for the Dielectric Resonator Antenna

The dielectric resonator antenna (DRA) has several advantages over metallic antennas, which may include low loss and compact design. However, few frequency reconfiguration methods exist for the DRA. This letter proposes, designs, and validates a new frequency-reconfigurable DRA that exploits the air gap effect. Here, air-filled channels are inserted between the DRA and the ground plane, and resonant frequency can be lowered by sliding metallized dielectric slugs under the resonator. The proof-of-concept prototype had a measured switching range of 24.7% and operating frequencies of 21.4 and 16.7 GHz.