Quad-Band Circularly Polarized CPW-Fed G-Shaped Printed Antenna with Square Slot

A compact quad-band circularly polarized (CP) G-shaped printed antenna with square slot is proposed in this paper. Two semicircular notches have been etched from lower periphery of the ground to increase the impedance bandwidth (IBW). In order to increase significantly the axial ratio bandwidth (ARBW), a spring-shaped notch is etched from the upper periphery of the ground. For further increase of ARBW and better impedance matching, another notch is etched from G-shaped radiating element. The proposed design exhibits simulated IBW = 22.046 GHz (8.954–31 GHz) with the center frequency fc = 20 GHz, and the measured IBW below –10 dB is from 8.8376 to 20 GHz. The IBW above 20 GHz are not measured due to limitations of the available VNA. The ARBW are 306.3 MHz (fc = 11.6 GHz), 363.1 MHz (fc = 21.3 GHz), 380.7 MHz (fc = 27.6 GHz), and 332.2 MHz (fc = 28.6 GHz), which are within the range of IBW. The maximum simulated peak gain is 5.46 dBi at 25.7 GHz. The proposed antenna is suitable for applications in the X-, K- and Ka-bands in the field of wireless communication.