Sidelobe level reduction in microstrip patch antenna array

The reduction in side lobe level (SLL) of a microstrip patch antenna array is discussed. For reducing the surface wave, air core within the substrate below each of the patch antennas is used and to reduce the mutual coupling between the array elements simple narrow strip fence between the elements are used. An array of 16 circular microstrip patch antennas fed through coaxial probes with appropriate Chebyshev amplitude distribution is considered. It is shown that application of the air cores and the narrow strips in the array results in an improvement of the SLL by 4.2 dB and 1.2 dB, respectively. Simulated return loss and pattern results obtained through two software packages of HFSS and CST are provided and results are discussed.