Wideband single‐layer patch antenna with stable high gain using characteristic mode analysis

Abstract

A low-profile single-layer patch antenna is proposed for bandwidth enhancement and stable high gain simultaneously. Firstly, coplanar parasitically coupled patches are introduced on two edges of the main driven patch to generate new resonant modes. The mutual compensation of modal electric energy and magnetic energy and the combination of modes lead to wideband performance based on characteristic mode analysis (CMA). Secondly, due to odd mode with unstable gain at high frequency, metallised vias are installed in the parasitic patches. Therefore, the symmetrical TM01 mode of parasitic patches is reshaped to the TM10 mode, and three in-phase TM10 modes are connected in parallel to generate stable high gain. The CMA is utilised to guide the transformation of unwanted modal behaviours into desired modal states. The achieved impedance bandwidth for −10 dB is 13.7% (4.96–5.69 GHz) with a gain of 6.86–8.53 dBi over the operating bandwidth.