Shared aperture printed slot antenna

Abstract

A circularly polarized (CP) printed slot antenna configuration on a shared aperture is proposed. Antenna is designed to operate at two distinct frequency bands of 4GHz and 8GHz. Dual slot CP elements at two frequencies are created on a common shared aperture and the antenna is fed by a single microstrip feed line. To achieve unidirectional beam, the slot antenna is backed by a stepped reflector. The stepped reflector is optimized to provide proper phase for pattern combining and axial ratio improvement at both the frequency bands. Antenna operates over a frequency range of 3.5 to 4.5GHz and 7.5 to 8.5GHz for a VSWR <;2. 3dB axial ratio beamwidth is 150 and 440 for 4GHz and 8GHz respectively on the shared aperture.