High-Gain Pattern-Reconfigurable Dielectric Resonator Antenna With Planar Feed for Switchable Beams Covering 360° Azimuthal Plane

Abstract

A high-gain, pattern-reconfigurable dielectric resonator antenna (DRA) with a switchable beam covering a 360° azimuthal plane is presented. It consists of a double-layer cylindrical dielectric resonator (DR) and a symmetric reconfigurable feeding circuit. The feeding network incorporates four microstrip-coupled slots, where the microstrip lines are connected to the ground via p-i-n diodes. This innovative planar feed excites two pairs of higher order DR modes, which can be modeled as equivalent magnetic and electric dipoles (M-E dipoles). The radiation superposition from these two pairs of modes significantly enhances both the antenna gain and impedance bandwidth. Additionally, the polarization of the equivalent magnetic dipole (M-dipole) modes can be controlled by the diodes, enabling beam switching across a full 360° azimuthal plane. Consequently, this planar feeding method serves as an effective replacement for the traditional combination of a feeding probe and four slots, greatly simplifying the antenna structure to facilitate the DR fabrication. To validate the design, two prototypes of four- and eight-beam configurations were simulated, fabricated, and measured. Both prototypes demonstrate high antenna gains exceeding 10 dBi, with their impedance bandwidths greater than 14%.