Design and Prototyping of High Gain Horn Antennas for Imaging Radar

Continuous wave radar with frequency modulation offers a promising solution for imaging applications in low visibility, obscure conditions. In this type of radar, two antennas are used; one for transmission and another for reception. In this paper, we present the optimal design of high-gain low-cost antennas for such imaging radars to operate in Sri Lanka’s unlicensed band within 2.4 – 2.5 GHz which also is an unlicensed band globally. The radar performance can be improved with a properly optimized pair of antennas at the transmitter and receiver. This paper presents the antenna design procedure we adopted along with simulations using CST Studio Suite 2021. Although we studied pyramidal horn and cylindrical horn antennas, we concluded that pyramidal horns are prohibitively large in size compared to cylindrical horns for comparable performance. The constructed cylindrical horn antennas were tested using a Vector Network Analyzer (VNA) and the test results well matched with the simulations. The antennas were also tested by including them in the radar prototype. The results of tracking performance with varying polarization modes indicate that the use of same polarization at the transmit and receive antennas give the best performance.