Results of further reduction of mutual coupling between Wang-shaped patch antennas are presented in this paper. Two methods were investigated: offset elements arranged in a rhombus lattice and that added with shorting posts. The posts are erected around each patch but not connected to the patches. To validate the methods, two planar 2-by-2 subarrays were designed and fabricated. Measurements agreed with the predicted simulations that all mutual coupling are suppressed below −15 dB within the impedance bandwidth of the subarrays.