Multifunction dielectric resonator antenna featuring omnidirectional switchable patterns

Abstract

This article presents innovative techniques for designing a multifunctional dielectric resonator antenna (DRA) system capable of omnidirectional switchable polarization and radiation patterns. The system comprises a four-port antenna and two back-to-back rectangular DRAs (RDRAs) mounted on a double-layer circular ground substrate. Each RDRA is excited by two orthogonal pole feeds via stripline for TE_1δ1/TE_δ11 mode operation, generating a bi-directional pattern. Eight rectangular slots on each ground surface form a defected ground structure (DGS), allowing precise control of ground plane currents and enabling dynamic beamwidth adjustment within the four-port antenna system. Strategic port selection facilitates a transition to reconfigurable omnidirectional radiation, offering linear polarization orientation and beam scanning across the entire sphere. The DGS also minimizes cross-polarization in these omnidirectional patterns. The article explores the underlying physics of beamwidth expansion and cross-polarization reduction. The four-port antenna with DGS achieves a 170° HPBW in the E-plane and 180° in the H-plane, with −16 dB port isolation, while reconfigurable omnidirectional patterns exhibit −25 dB cross-polarization suppression. Simulations using Ansys HFSS and CST Studio, along with prototype fabrication and testing, validate the four-port antenna performance and reconfigurable omnidirectional functionalities. This proposed antenna is suitable for Wi-Fi, 5G, and other modern communication applications.