Magnetic quadrupole mode excitation of a cylindrical dielectric resonator antenna using planar feed

Abstract

In this article, excitation of the magnetic quadrupole mode of a cylindrical dielectric resonator antenna, designated as the HEM21δ mode, using planar feeding technique is discussed for the first time. Two types of planar feeds—a dual-microstrip feed and a dual-slot feed are numerically investigated. Results show that the dual-slot feed is more suitable for exciting the HEM21δ mode as it gives better symmetry of the radiation pattern and lower cross-polarization level. A DRA prototype (dielectric constant, εr = 24, loss tangent, tanδ = 0.002, diameter, 2a = 19.43 mm and height, h = 7.3 mm) using dual-slot feed is fabricated and characterized. Measurements demonstrate a resonant frequency of ~ 4.96 GHz, bandwidth of ~4.4%, peak gain of ~3.45 dBi and peak cross-polar level of ~ − 11 dB for the HEM21δ mode, which are in decent agreement with numerical predictions.