Analysis of the coupling between degenerate modes of enclosed rectangular microstrip patches

Coupling between degenerate modes of a square patch caused by a square corner cutout is examined. The effect of a corner cutout on the coupling between modes of two adjacent patches is also discussed. The problem is formulated using the electric field integral equation in the spectral domain, and solved with the method of moments. Two types of basis functions were used: full domain functions, with the edge condition, and subdomain basis functions. Results are presented showing the coupling between modes, both for a single patch and for coupling between two patches.< >