A Feasibility Study to Practically Implement a High-Performance Circularly Polarised Antenna Array for Point-to-Point Wireless Communication

This article presents the design, fabrication, and experimental validation of a compact linear series-fed microstrip antenna array with dual circular polarisation (CP) capability. The proposed structure consists of a 4 × 4 slotted circular patch array excited via four microstrip lines using a coplanar proximity coupling technique. Dual-CP operation is achieved through two miniaturised and distinct microstrip power divider networks, enabling the generation of either left-hand or right-hand CP based on the excitation port. To maximise gain and efficiency, the design reduces feedline branching and employs optimised slotted patch elements, resulting in low power loss and high radiation efficiency. The antenna achieves a realised peak gain of 19.4 dBic across 12.2-12.7 GHz and a 3-dB axial ratio bandwidth from 11.9-13.1 GHz. Simulation and measurement results demonstrate excellent agreement. Thanks to its compact size, wide bandwidth, dual-CP functionality, and high gain, the proposed antenna offers a promising solution for point-to-point wireless communication systems. Compared to existing multi- and single-layer microstrip-based CP arrays, this work introduces a simplified feed structure and improved performance, demonstrating clear advancement in antenna array design.