High Gain Low-Profile Omnidirectional Yagi-Uda Array Antenna

This paper proposes a novel Yagi-Uda array antenna that can realize high gain omnidirectional pattern under a low profile of 0.11λ0. The proposed antenna is composed of a via-shorted circular patch antenna as the driven element and three annular open-cavity magnetic dipoles as directors. The overall structure is both rotational symmetric and symmetric about the azimuth plane, which leads to a symmetrical pattern in the elevation plane and omnidirectional high gain pattern in the azimuth plane. Simulation results show that the proposed antenna can work in the impedance bandwidth from 4.82 GHz to 5.4 GHz (10.9%). The peak gain of antenna is 4dBi at 5.3 GHz with good omnidirectivity. Thanks to the open-cavity magnetic dipole directors introduced, compared with the case with only the driven element, the omnidirectional gain is improved by 5.7 to 7.8dBi.