A Wideband Halo Antenna with Three Resonance Characteristics

Abstract

A Halo antenna has the horizontally polarized and an omnidirectional radiation pattern in the horizontal plane. A Halo antenna operates when the circumference is about 0.5 wavelength, and the relative bandwidth is narrow. In this paper, we study the Halo antenna with three resonance characteristics by loading four parasitic elements with different gap angles. As a result, it is confirmed that the diameter and the relative bandwidth of the proposed antenna are 0.128λ (λ: the wavelength of the lowest operational frequency) and 12% (|S₁₁| ≤ −10 dB). Furthermore, the radiation patterns are the horizontally polarized and omnidirectional within the operating band.