Circularly polarized aperture-coupled circular microstrip patch antennas for L-band applications

Circularly polarized aperture-coupled circular microstrip patch antennas are investigated with the goal of obtaining an 8% impedance and ellipticity bandwidth in the L-band. Three varieties-a single-feed patch with perturbation segments, a single-feed stacked patch with perturbation segments, and a dual-feed patch with a 3-dB branch line coupler as an external polarizer are considered to obtain the required performance. All the three investigated patch configurations meet the impedance bandwidth requirement, but only two varieties: the single-feed stacked patch and the dual-feed patch meet the required ellipticity bandwidth. These antennas feature more than 9-dBi gain. They use low-cost substrates and foam for bandwidth enhancement and, hence, they are attractive for applications where the production cost is of importance