Triple-Band Unidirectional Circularly Polarized Hexagonal Slot Antenna With Multiple L-Shaped Slits

The design of a triple-band circularly polarized hexagonal slot antenna with L-shaped slits is presented in this study. By adding three L-shaped slit arms to the hexagonal slot, circularly polarized radiation is achieved at three different frequencies. The proposed slot antenna is excited by a simple tapered microstrip feeding line. A conducting reflector is also used to enhance the antenna gain. The measured -10 dB reflection bandwidths are 33.16% (3.22-4.5 GHz) and 22.72% (4.76-5.98 GHz). The measured 3 dB axial ratio bandwidths for the triple bands are 1.7%, 3.86%, and 5.23%, respectively. The measured peak gains within the 3 dB axial ratio bands are 5.5 dBic, 4.63 dBic, and 6.77 dBic.