Polarisation reconfigurable dual‐band circularly polarised patch antenna with defected ground plane for C‐band wireless applications

Abstract

Here, a novel geometry of dual-band polarisation reconfigurable patch antenna is presented. The proposed prototype design consists of two orthogonal arms as a patch, an inclined slotted asymmetric pentagonal-shaped ground plane and a PIN diode with a biasing circuit. The polarisation reconfiguration is controlled via ON/OFF states of the PIN diode. The unique feature of the proposed antenna design is that it provides polarisation reconfiguration without considerable deviation in −10 dB impedance bandwidth (IBW) frequency response. The proposed antenna has a measured −10 dB IBW of 49.28% (3.96–6.55 GHz) and 41.47% (4.3–6.55 GHz) in the ON-state and OFF-states of the PIN diode, respectively. In the ON-state of the PIN diode, the antenna exhibits a dual-band circular polarisation. The first 3 dB axial ratio (AR) band is 4.5% (4.3–4.5 GHz) and the second 3 dB AR band is 17.69% (5.1–6.09 GHz). The proposed antenna exhibits almost uniform gain over the entire operating axial-ratio bandwidth, with peak CP gain of 2.8 dBic. The suggested antenna has a wide −10 dB IBW, and it is suitable for C-band wireless applications.