High‐gain wideband circularly polarised mm‐wave antenna with highly symmetrical radiation patterns

A circularly polarised (CP) antenna with highly symmetrical radiation patterns and wide operating bandwidth is presented for millimetre‐wave (mm‐wave) applications. By loading four parasitic inverted‐F components around a SIW‐fed S‐dipole antenna, better axial ratio (AR) performance and higher gain performance are realised. Furthermore, the proposed antenna can achieve highly symmetrical radiation patterns in different elevation planes within a wide operating band. This unique feature makes it advantageous to more uniform signal coverage. To verify the effectiveness of the antenna, a prototype is fabricated and measured. The experimental results validate that the antenna covers the impedance bandwidth of 49.1% (21.2–35 GHz) and the AR bandwidth of 51.3% (20–33.8 GHz). Besides, the antenna peak gain can reach 10.42 dBic at 28.5 GHz. More importantly, the antenna can radiate extremely symmetrical and uniform waves in different elevation planes within a wide operating band (21–29 GHz). Attributed to these merits, the presented antenna shows great potential in various mm‐wave systems.