The propagation wavenumber for microstrip line in the first higher-order mode

This paper presents equations for calculating the propagation wavenumber for a microstrip line operating in the first higher-order mode. The transverse resonance method is used for determining the propagation wavenumber. Previously, Oliner used the transverse resonant method but only considered the self admittance of the open edge. In this paper, the mutual admittance between the two open edges of the microstrip line is also considered. By accounting for the mutual admittance, the accuracy of the wavenumber is greatly improved.