MUTUAL COUPLING COEFFICIENT BETWEEN 2 RECTANGULAR MICROSTRIP ANTENNA ELEMENTS WITH VARIOUS SUBSTRATE THICKNESSES

A volume equivalence theorem combined with a theoretical model equival ent to a lossy transmission line and the cavity model yields a new alg orithm that is much simpler than the presently used methods for calcul ating mutual coupling coefficients between two identical probe-fed rec tangular microstrip antenna elements with various substrate thicknesse s. The theorem takes into account surface-wave contribution, losses as sociated with radiation dielectrics and conductors through their equiv alent resistances and/or quality factors, mismatching physical propert ies of the antenna elements, relative permittivity, and thicknesses of substrates. Numerical coupling coefficient results that illustrate th e approach and the measured results for the dominant TM10 mode are pre sented as a function of separation between two antenna elements in E- and H-plane coupling configurations. Numerical results are in good agr eement with measurements. (C) 1997 John Wiley & Sons, Inc.