Circularly Polarized Single-Layer Microstrip Reflectarray Fed with a 2x2 Microstrip Patch Array

The design of a single-band singly-layered reflectarray fed by a circularly polarized 2x2 microstrip patch antenna array with corporate feeding to be used in K-band (18.7–19.2 GHz) is proposed in this paper. It is demonstrated by simulations and measurements that the axial ratio bandwidth performance of the reflectarray depends strongly on the circularly polarization purity of the feeder. Simulated and measured results revealed that the complete reflectarray exhibits good performance in terms of input impedance with -10 dB input reflection coefficient bandwidth of 19.0 %, radiation pattern with 3 dB axial ratio bandwidth of 10.55 % and 3 dB gain bandwidth of 2.64 %.