Element positioning applied to a low sidelobe level GSM base station array antenna design using genetic algorithm

Element positioning is an effective approach in achieving low sidelobe level array antennas. In cases with few number of elements it becomes almost the best applicable solution. In this paper, the approach is applied to a 5times1 array antenna designed for GSM´s BTS antenna application and the sidelobe reduction process and results are compared to that of phase only optimization. The sidelobe levels depend on element dimensions and the process highly clarifies the importance of element shrinking, which imposes a limit on the minimum possible sidelobe level. By considering element dimensions between lambda and 0.4 lambda, sidelobe levels ranging from -12.7 dB to -16.7 dB are derived using a genetic algorithm which could be quite satisfying for a 5-element equi-phase array