A Single-Layer Planar Array Antenna Using Circularly-Polarized Reconfigurable Elements for Conical-Beam Radiation

Abstract

This article proposes a novel planar array antenna for reconfigurable circular polarization (CP) with conical-beam radiation. The array consists of four radiating elements and a two-dimensional (2D) switchable feed network. Each element can switch CP using the proximity gap-coupled branches, augmented by a simple bias-decoupling mechanism through outstanding single-layer integration. Its symmetrical configuration also ensures consistent performance for the intended functionality during the switching operation. The initial optimization primarily focuses on CP reconfiguration in a single element, followed by the array design for conical-beam radiation. The effectiveness of this single-layer-based design technology is further validated through the fabrication of a $2\times 2$ array. The measured results reveal the 10-dB impedance bandwidth of 4%, 3-dB axial ratio (AR) bandwidth of 1.6%, and peak realized gain of 6.8 dBic. Also, the array successfully generates the conical-beam radiation with CP switching capability.

Keywords

• Bias decoupling
• circular polarization
• conical beam
• electrical reconfiguration
• proximity gap-coupled feed