A Double Layer Circularly Polarised Radial Line Slot Array Antenna with Uniform Aperture Illumination

In this paper, we have designed and investigated a double layer circularly polarised radial line slot array (RLSA) antenna for satellite communication. The antenna is composed of twofold radial waveguide with slots acting as radiating elements on its surface. The radiating slots are arranged in a spiral pattern on the antenna aperture. Every slot has a particular length and position. The slots are oriented in a way to intercept the radial currents on the upper waveguide. The slot lengths were varied to achieve a uniform aperture distribution. The electromagnetic power is fed from center of the lower waveguide. Numerical results show that the antenna is well matched within the operating frequency range. The far-field results indicate a peak directivity of 27 dBi at 20 GHz with a good pattern quality and lower side lobe level of -27.2 dB.