A Novel Ultra Wideband Circularly Polarized Antenna for Millimeter Wave Communication

An ultra-wideband circularly polarized microstrip antenna suitable for millimeter-wave communication is proposed. To meet the demand of channel capacity in millimeter-wave communication system, the antenna uses nested circular oscillators with defective ground design to achieve the ultra-wideband characteristics of the antenna, and the dual-frequency circular polarization characteristics of the antenna are achieved by opening X-shaped slots for the internal radiation unit. The antenna has a small size of 4.6x3.5x0.254 mm(3). The results show that the -10dB bandwidth of the antenna is 53% (26.7GHz-43.8GHz), which can cover N258, N259, N260 and N261, and has circular polarization characteristics in the 28 and 38 Ghz bands. The measured peak gain was 5.7dBi at 28 GHz and 7.1dBi at 38 GHz. Therefore, the antenna proposed in this research has good applications value in millimeter wave communication systems.