Sidelobe Level Reduction of BTS Array Antennas Using Genetic Based Element Positioning

Uniform reduction of inter-element spacings in an array antenna will clearly reduce its sidelobe level ratio (SLR). In this paper, optimum spacings are derived using a genetic algorithm (GA) and the SLR reduction process is compared with the uniform case. The method is applied to a 5times1 microstrip BTS array antenna. Results show about 1 dB improvement in SLR compared to the uniform array with the same total size. This improvement is verified for different array sizes ranging from 0.9 lambda to 0.4 lambda. It is equal to a down-shift in SLR/(array size) diagram.