Single-feed circularly polarised aperture-coupled square ring slot microstrip antenna

Abstract

A novel single-feed circularly polarised aperture-coupled square patch\n\nis presented, where a square ring slot has been adopted to implement\n\nthe coupling mechanism. By introducing some simple modifications\n\nof the square ring and patch geometries (namely a couple of meanders\n\nand slots), a 3 dB axial ratio fractional bandwidth of up to 9% is\n\nachieved. Explicit reference is made to the design of a WiMax\n\nantenna operating in the 3.3–3.8 GHz frequency band. The antenna\n\nhas been fabricated and characterised.