CLOSED-FORM EXPRESSIONS FOR COMPUTATION OF MUTUAL ADMITTANCE OF A CLASS OF GAP-COUPLED CIRCULAR MICROSTRIP ANTENNAS

摘要

In this paper, a new set of expressions are presented, which leads to accurate estimation of the mutual admittance and mutual coupling thereof for gap-coupled circular microstrip antennas. Unlike previous works, the field expressions for both the patches are obtained with respect to one coordinate system, and the circuit theory is used to obtain the admittance parameter. When this mutual admittance is converted to scattering parameters, we obtain the magnitude of mutual coupling. The results presented in the standard literature are compared with those obtained through the present formulation and the accuracy obtained is reasonably good. The method is also extended to incorporate the effects of shorting pins at the center of the two patches.