Wideband Gain Enhancement of an AMC Cavity-Backed Dual-Polarized Antenna

Abstract

A novel low-profile wideband antenna is proposed with high-gain, high-isolated, and dual-polarized properties. It consists of two mutually-orthogonal bowtie-shaped dipole radiators, four rectangular parasitic elements, and a cylindrical artificial magnetic conductor (AMC) cavity. By introducing parasitic elements, additional resonance is generated, and the bandwidth is widened. The gain is mainly improved by the cylindrical metallic wall and wideband AMC of the cavity. The AMC operates in ±90 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sup> reflection phase band-gap bandwidth of 2.35-4.25 GHz, and its equivalent circuit model is developed to understand the working mechanism. The orthogonal placement of two dipole radiators ensures polarization diversity and high isolation. The impacts of various environmental conditions on antenna performance are investigated. To verify the concept of design and demonstrate its excellent performance features, a prototype is fabricated and measured. The proposed wideband antenna has a height of 0.18 wavelength at the center frequency. The measured -10-dB impedance bandwidth is from 2.16 to 3.96 GHz, where the realized gain is 8.34-10.96 dBi and the radiation efficiency is more than 81.8%. High isolation of > 28.65 dB and low envelop correlation coefficient (ECC) of < 2.74 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> are also achieved between antenna elements. It can be used in the base station for intelligent Internet of Vehicle (IoV) applications, covering the bands of WLAN, WiMAX, Bluetooth, LTE, and 5G sub-6 GHz.