Director-Loaded Magneto-Electric Dipole Antenna With Wideband Flat Gain

Abstract

In this paper, a novel wideband magneto-electric (ME) dipole antenna with flat gain is proposed. The proposed antenna consists of a normal ME dipole antenna element, a substrate-printed director, and a horn-like reflector (HLR). The combination of the director and ME dipole antenna element allows the proposed antenna to work as a quasi-Yagi antenna at high frequencies, which enhances its gain and front-to-back ratio (F/B ratio). The director also improves the impedance matching of the antenna, allowing a wide operation bandwidth. Using the degrees of freedom of the HLR, one is able to tune the antenna gain in separate frequency bands, opening the possibility to reach the most important characteristic: a very stable gain in a wide frequency range. A prototype was fabricated and measured. The measured −10 dB bandwidth is from 1.6 to 3.8 GHz. Within the designated frequency range (1.7–3.7 GHz, incorporating the operational frequencies for 2G, 3G, 4G, Wi-Fi, and WiMax), the measured gain variation is only 0.45 dB.