High-gain 28-GHz CP Patch Antenna with 6×6 FSS

The presented design offers a novel miniaturized single-feed circularly polarized (CP) microstrip patch antenna in conjunction with a 6×6 frequency selective surface (FSS) for gain improvement in Ka-band (28 GHz) applications. The proposed CP microstrip antenna uses the truncated corner microstrip patch design in order to obtain circular polarization and at the same time remains compact enough for future millimeter-wave wireless systems. In order to improve the radiation efficiency of the proposed design, the use of symmetric closed-ring 6×6 FSS is implemented above the radiating patch. Electromagnetic coupling between the antenna and FSS results in improvement of radiation characteristics of the antenna and increase in its gain. The reference CP antenna gives the gain of 7.28 dBi, impedance bandwidth of 2.72 GHz (9.74%) and 3-dB axial-ratio bandwidth of 1.97 GHz (7.12%). As a result of incorporation of the FSS layer, the gain is increased up to 11.01 dBi, which is equivalent to 3.73 dB of improvement in gain. Impedance and axial-ratio bandwidths become equal to 2.31 GHz and 1.74 GHz respectively. Results reveal that the developed FSS using single-layer configuration provides an efficient and low-complexity approach to enhance gain without affecting the impedance or polarization bandwidth performance. Considering its small size, high gain and circular polarization properties, the developed antenna is suitable for use in Ka-band satellite communications and 5G/6G millimeter-wave communication applications.