Effect of mutual coupling between feed elements on integrated lens antenna performance

An integrated lens antenna (ILA) equipped with a beam-switching array feed provides beam-steering. This study investigates the effects of the mutual coupling between the feed array elements on the ILA performance. A simulation study of an ILA with two different feed types with varying mutual coupling levels is done. Radiation pattern and boresight directivity of the ILA are in the prime focus of the study. An aperture-coupled microstrip patch antenna (ACMPA) and a stacked ACMPA feeds embedded in an array are used to study the radiation characteristics of the ILA. Results show that changes in directivity and radiation pattern of the feed caused by the mutual coupling have significant impact in the ILA characteristics. However, it is found that the mutual coupling level alone does not predict well the changes in the ILA radiation. Among two feed antenna types with similar mutual coupling variation, the stacked ACMPA feed with less radiation pattern distortion gives better ILA performance compared to the ACMPA feed with significant radiation pattern distortion. Furthermore, impact of the port impedance mismatch of the adjacent inactive antennas on the active element performance of a beam-switching feed network and its corresponding impact on the ILA is investigated.