Upper Bound Calculations on Capacitance of Microstrip Line Using Variational Method and Spectral Domain Approach

In this paper, the authors have employed an analytical approach based on the Fourier transformation and variational techniques in terms of the surface potential of the dielecric sheet to find the upper bounds of the microstrip line capacitance. It is hoped that our work will complement that of Yamashita et al., who calculated the lower bounds dealing with the charge density on the surface of the conductor strip, in estimating the margins of error in calculation.