Miniaturised design of coplanar waveguide‐fed broadband circularly polarised slot antenna

A novel miniaturised design of broadband circularly polarised (CP) antenna using a coplanar waveguide feed is presented. To realise CP characteristic, a pair of inverted‐L strips around two opposite corners of the slot is protruded. By properly folding the modified ground plane, the 3‐dB axial‐ratio (AR) band is shifted to around a lower‐frequency location, whereas the input impedance band is shifted downwards through the Y‐shaped loading strip. The overall size of the antenna is about 0.34 λ 0 × 0.34 λ 0 × 0.009 λ 0 at 1.7 GHz. Measured results show that the proposed design can deliver 3‐dB AR bandwidth of 36.8% (1.55–2.25 GHz) and 10 dB impedance bandwidth of 63.2% (1.17–2.25 GHz).