A Radial Line Slot Array Antenna with Improved Radiation Patterns for Satellite Communication

In this paper we have investigated aperture field distribution of a radial line slot array (RLSA) antenna to improve the radiation pattern quality. A circularly polarised (CP) RLSA antenna was designed with tapered amplitude distribution. The distribution was obtained by manipulating the slot lengths on the antenna aperture based on a slot coupling analysis. The antenna has achieved a peak directivity of 31.7dBic and a peak gain of 31.3 dBic at 19.3 GHz. A significant improvement has been achieved in reducing side lobe levels. The antenna has demonstrated a side lobe level of -28.8 dB in ϕ = 0° plane and -32.2 dB in ϕ = 90° plane at 19.3 GHz.