Design of a Variable Depth Axially Corrugated Horn Antenna at X-Band for Low Cross-Polarization Applications

In this paper, the design of an axially corrugated conical horn antenna is presented for the application in a transportable polarimetric Doppler Weather Radar (DWR) at X-Band. Such types of applications require very low cross-polarization and the same is achieved for the current feed horn. Additionally, since it is to be used for transportable weather radar and the actual operating frequency depends at the corresponding site condition, the horn has been designed to operate the commonly used weather radar band of 9.3 GHz to 9.5 GHz. The proposed feed horn has five corrugations with variable depth and linear profile for the ease of fabrication. The horn was fabricated using aluminium material and measurements were carried out in Compact Antenna Test Facility (CATF). Measurement result confirms -18 dB of edge taper as requirement with a cross polarization of better -30 dB which are in good agreement with the simulated one. Measured data of the feed pattern is used to simulate in GRASP9 software package and the overall antenna performance ensures the fulfilment of required specifications for the polarimetric Doppler weather radar system.