Compact dual‐band dual circularly polarised annular‐ring patch antenna for BeiDou navigation satellite system application

Abstract

A compact rectangular‐ring patch antenna with dual bands and dual circular polarisation is proposed for BeiDou navigation satellite system (BDS) application in this study. The compactness of the proposed antenna can be realised through using a rectangular‐ring radiation patch for the higher band and a meandered‐line‐shaped ring radiation patch for the lower band. The radiation patches are stacked and printed, respectively, on the two layers of substrate separated by an air gap. Two pairs of inverted‐L shaped strips and perturbation structures are inserted in two radiation patches, respectively, to achieve circularly polarised radiation in dual bands. Specifically, arc‐shaped coupled feeding lines are employed to obtain preferable impedance matching. Simulated and measured results show a good performance such as a compact size of 0.201 λ g × 0.201 λ g × 0.076 λ g , satisfactory 10‐dB return loss bandwidths (1595–1632 MHz, 2395–2574MHz) and desirable directional radiation patterns with the antenna gain of nearly 4.3 dBic at 1615.68MHz and 6.4 dBic at 2491.75MHz.