Pattern Synthesis of Substrate Integrated Waveguide Leaky-Wave Antennas Using Optimization Algorithm

In the modern era, the antennas with cosecant squared pattern play a significant role in radar applic ations. These applications are used to cover an airspace to search for targets and estimate their height. In this article, a method is proposed for the synthesis of cosecant squared pattern using leaky wave antenna. The principal mechanism in the leaky wave antennae is wave attenuation due to power leakage while the wave propagates through the structure. Thus, by controlling the leakage and phase constants along the length of the structure, one can synthesize the desired radiation patterns. We have used the genetic algorithm to optimize the leakage constant and obtain the desired cosecant squared pattern In the range of 10 to 30 degrees. Conformity in simulation results and measured results indicates accuracy in the design process. The proposed method obtains the desired pattern with a ripple of less than 2 dB in the designated area and side lobe level less than -18 dB, which makes the antenna suitable for radar applications.