Beamwidth and Bandwidth Enhancement of a Dual-circularly Polarized Microstrip Patch Antenna

This article presents a implementation of a microstrip patch antenna that achieves wideband and wide beam performance, while maintaining enhanced bandwidth. Herein, the antenna utilizes dual ports with a 90° phase difference for excitation, enabling circularly polarized radiation. To enhance the beam width, a metal cavity is introduced around the double-layer circular patch, effectively broadening the beam width for both low and high frequencies through the coupling effect of the metal cavity on the radiation field. Simulation results indicate that the coupling of the metal cavity introduces new resonance points, thus enhancing its bandwidth. Furthermore, a dielectric cavity with a metal floor is incorporated below the antenna, along with a dielectric matching layer above the antenna. By carefully selecting the height of the dielectric cavity and the size of the matching layer, the beam width of the antenna is significantly expanded while ensuring minimal impact on the antenna’s bandwidth. The simulation results that the half-wave power beamwidth of the antenna at low, intermediate, and high frequencies is approximately 169±9°, 206±13°, and 190±1°, respectively. Additionally, the antenna maintains a wide impedance bandwidth of 20.2%.