Frequency-Tunable Dielectric Resonator Antenna Using a Piezoelectric Bending Actuator

This article investigates a frequency-tunable dielectric resonator antenna (DRA) using an electromechanical approach. To change the frequency, four movable cylindrical dielectric posts are inserted into the DRA to perturb the field inside DRA. A piezoelectric bending actuator is introduced to control the movement of the dielectric posts. By adjusting the dc bias voltage of the piezoelectric bending actuator, the dielectric posts can move up and down to alter the frequency of the DRA dynamically. As compared with most existing frequency-tunable DRAs, our design has a high antenna efficiency because it does not need any lossy frequency-tunable devices, such as varactors or p-i-n diodes. Also, our design has one variable bias voltage port only, being needless to design any dc bias networks. For demonstration, a frequency-tunable DRA prototype was designed, fabricated, and tested. Measured result shows that its antenna performance is very stable across the tunable frequency range, with the peak total antenna efficiencies higher than 90%.