A dual circularly polarized patch antenna for broadband millimeter wave (MMW) communication systems

An aperture coupled circular patch antenna is presented for dual circular polarization at Ka-band. Two microstrip lines are used to excite a circular patch through two slots to generate a broadband RHCP and LHCP radiation with high isolation between them. An aperture coupling is employed to provide a wide beamwidth axial ratio. The proposed antenna is a good element candidate to be considered for compact polarization reconfigurable phased array antennas. The simulated results of the presented antenna show a10 dB impedance bandwidth of more than 15.1% with very good isolation bandwidth. Furthermore, it shows a 3 dB axial-ratio of 13.9% at 30 GHz. Additionally, it acquires an axial ratio less than 3 dB over ± 50. beamwidth for 2.2 GHz bandwidth.