SIW Cavity-Backed Ultrawideband Cirularly Polarized Slot Antenna

A new design of substrate integrated waveguide-based cavity backed slot antenna for ultrawideband application is introduced in this paper. This new circularly polarized Bow-Tie slot antenna is taken for circular polarization in ultrawideband frequency band (9.65 GHz to 10.26 GHz). The proposed slot radiator is designed using a single substrate having height of 0.787 mm, which make this radiator low profile, easy integrable with other circuits and cost effective. The proposed antenna is designed using two cross bow tie slots etched at the bottom metallic conductor and coplanar waveguide feed on the top conductor. The radiation characteristics of the proposed cavity backed broadband bow-tie slot radiator is better than traditional cavity backed slot antenna. Slot radiator backed by SIW cavity were taken because of its high gain and better front-to-back ratio. At the resonating frequency the designed prototype shows a bandwidth of 0.1227 GHz (12.27 %), gain of more than 5 dBi. For the complete half-power beamwidth, the axial ratio is found to be below 3 dB.