Vertically Polarized, Pattern-Reconfigurable, Yagi–Uda Dielectric Resonator Antenna

In this letter, we propose a novel vertically polarized pattern-reconfigurable dielectric resonator antenna. A cylindrical dielectric resonator (DR) operating in vertically polarized and omnidirectional TM<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01δ</sub> mode is excited by a central probe. Based on the Yagi principle, we innovatively introduced four top-loaded copper columns integrated into DR to surround the probe as controllable reflectors. Consequently, one original omnidirectional and eight directional patterns with 45° steps can be easily switched by manipulating four PIN diodes. Due to its high permittivity and the unseparated reflectors, it features a compact size of π×0.16λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub><sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>×0.14λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub>, simple structures, and a brief control mechanism. The overlapping bandwidth of the antenna is 2.62 GHz to 2.82 GHz (7.4%). Its average peak gains are about 4 dBi in the omnidirectional state, and 5.6 dBi/5.4 dBi in the directional states. The proposed antenna shows great potential for miniaturized indoor wireless communication to enhance target radiation and provide wide coverage.