A New Strategy to Design Microstrip Antenna Array with Low Side-Lobe Level and High Gain

A new strategy for designing low side-lobe level (SLL) antenna array is presented. This strategy utilizes special arrangement of antenna elements rather than direct tapered excitation amplitude to obtain an equivalent desired amplitude distribution in the main planes and thus achieve low SLL and high gain concurrently. To illustrate the strategy, 9-element microstrip antennas are arranged in four manners. An equivalent analysis method is also proposed to predict the SLL of the arrays. Using this method, a fast analysis of the trend of a microstrip array for a low SLL can be performed and thus a proper array-element arrangement is acquired. Both numerical and experimental results demonstrate that the SLLs in E and H planes of the novel array are fairly low. Meanwhile, the main beam of the novel array is almost the same with that of a conventional high-gain array. The antenna arrangement manner and the proposed strategy are particularly suitable for applications when low SLL and high gain are both demanded.