Analyzing the Coupling from Radiating Slots in a Double-Layered Radial Line Slot Array Antenna

This paper investigates power coupling out of radiating slots in a double-layered circularly polarised radial line slot array (RLSA) antenna. The antenna is composed of three plates which form a folded radial waveguide and supports inward-travelling waves. Top plate of the antenna has radiating slots. The slots are designed to intercept the currents on the radial waveguide and produce a circularly polarised broadside beam. The slot length is varied using coupling factor in order to achieve a uniform aperture distribution. The simulation results show that the antenna has fairly uniform phase distribution in its near field. The far-field result indicates a peak directivity of 26.4 dBic at 20 GHz with a good pattern quality and a side lobe level of -21.8 dB.