Substrate integrated waveguide dual-frequency dual-sense circularly polarized cavity-backed slot antenna

A novel design of dual-frequency dual-sense circularly polarized (CP) substrate integrated waveguide (SIW) cavity-backed slot antenna is presented for dual-band wireless communication systems. The proposed antenna consists of square SIW cavity, asymmetrical bow-tie-shaped cross slot and probe feed. Due to use of asymmetrical bow-tie-shaped cross slot, circularly polarized wave radiates at two different frequencies with opposite sense of polarizations. The RHCP radiation occurs at (10.45-10.54) GHz (Lower band) and LHCP occurs at (11.26-11.34) GHz (Upper band). Moreover, in each band, sense of polarization can be change by changing the feed position. The front to back radiation ratio (FTBRR) is more than 10.5 dB and cross polarization level is lower than -20 dB in both the bands.