Dual Circularly Polarized Wide Beamwidth Microstrip Antenna Backed by Choke Ring for S-Band

Design methodology, fabrication and measurement results of a dual circularly polarized, wide beamwidth antenna operating in S-band are presented in this paper. The antenna comprises of a microstrip patch assembly placed on top of a metallic choke ring. The microstrip assembly consists of two substrates stacked to each other. A dual probe fed circular patch and parasitic crossed dipoles are printed on one substrate, while a 90° hybrid coupler connecting the two feeds is printed on other substrate. The antenna exhibits a 17 dB return loss bandwidth of more than 8%. This design has a stable phase centre and exhibits realized gain greater than 0 dBi with axial ratio less than 3 dB for low elevation angles (± 25°) for both polarizations. Results of RF characterization and farfield measurements of the antenna have been included, which are observed to be in close agreement to the simulated results.