Design and Analysis of a Series-Fed Aperture-Coupled Antenna Array With Wideband and High-Efficient Characteristics

In this paper, a new wideband series-fed antenna array is proposed and analyzed. The antenna array structure consists of two antennas with two ports, two antennas with one port, and a wideband 180° coupler. A portion of power is propagated by the antenna with two ports, and the rest is propagated by the antenna with one port. A new wideband 180° coupler is designed in order to make the feed structure as compact as possible and to be integrated with the antenna array. Due to using elements with wideband structure, the overall antenna is wideband with measured bandwidth of 40% with reflection coefficient of 10 dB and 3 dB gain deviation from 3.85 to 5.75 GHz. The measured peak gain of 13.4 dBi has been achieved for the proposed 1 x 4 antenna array. The measured results shows that the efficiency is better than 87% and side lobe level at the frequencies of 4.6 and 5.4 GHz are, respectively, nearly -14 and -12 dB.