Sequentially rotated gap-coupled circular slot cut circular microstrip antennas

Circular polarized microstrip antennas are required in applications wherein an uncertainty in the direction of received signal polarization exist. In this paper an offset slot cut circular microstrip antenna to realize circular polarization in 1000 MHz frequency band is proposed. It yields axial ratio bandwidth of 10 MHz (∼1.2%). To increase the axial ratio bandwidth its gap-coupled array configuration with parasitic offset circular slot cut circular patches is proposed. A maximum return loss and axial ratio bandwidth of nearly 44 (∼4.5%) and 18 MHz (∼2.0%), respectively is obtained in gap-coupled configuration of circular patches along y-axis. The proposed configurations yields broadside radiation pattern over entire bandwidth with antenna gain of more than 4 dBi in their suspended variation. The proposed gap-coupled array configuration can find applications in mobile communication environment in 1000 MHz frequency band.