Mutual coupling and mitigation in two-dimensional phased arrays based on planar quasi-Yagi antennas

The planar quasi-Yagi antenna we developed recently promises the realization of 2D active phased arrays with optimal array bandwidth and scanning range. This paper addresses the issue of mutual coupling between quasi-Yagi elements to ensure scan-blindness-free construction of a 2D array. While the coupling between two λ₀/2-spaced quasi-Yagi elements is reasonably low (-25 dB in E plane, -20 dB in H plane) in its original design, it is found by both simulation and measurement that the coupling levels can be pushed to below -30 dB in both planes by cutting a slit in the dielectric in the E plane and adding a metal fence in the H plane, making it possible to realize full 2D phased arrays which are free of scan blindness over a wide range of frequency and scan angle