Theory of of Dispersion in Microstrip Arbitrary Width

An analytic theory for the dispersion of the fundamental mode on wide open microstrip is presented. Only a single basis function is needed to accurately represent each of the change and current distributions on the strip, thus allowing more efficient determination of the propagation constant as compared to moment-method solutions requiring a larger number of basis functions. The results obtained blend smoothly into results of high-frequency (Wiener-Hopf) theories, and still retain the appealing physical interpretation in terms of capitance and inductance of the narrow strip theory previously obtained by the authors.