Designing a Broadband Circularly Polarized Patch Antenna Array for Millimeter-Wave Beamforming

A 2×2 corporate-fed microstrip patch antenna array with broadband and circularly polarized characteristics was developed to investigate the millimeter-wave beamforming technique. A beamforming network that provides equally divided power and true-time delay progressive phase shifts was deployed to provide the corresponding rotation phase to each array element. A high gain and circularly polarized radiation pattern over a wide-frequency range was obtained at the array’s broadside. The impacts of the broadband operation are evaluated and discussed. The broadband and circularly polarized characteristics of our proposed array are ideal for modern communication systems.