A Galerkin analysis of microstrip circuits of arbitrary plauar geomehy enclosed in a rectangular conducting box is described. The technique entails a time-harmonic electromagnetic analysis evaluating all fields and surface currents. This analysis is suitable for the accurate verification of microstrip designs prior to fabrication. A computer program implementing the analysis has been written in Pascaf on a persomd compnter. Agreement with measurements of severaf microstrip strnctores suggests a high degree of accuracy.

This paper describes and rigorously validates single-and multiple-layer models of microstrip conductor loss appropriate for high-accuracy application in electromagnetic analysis software. The models are validated by comparison with measurement and by comparison with converged results. It is shown that in some cases an extremely small cell size is needed in order to achieve convergence. Several effects that make a significant contribution to loss and are not modeled by the classic square root of frequency loss model are investigated including dispersion and current on the side of transmission lines. Finally, the counterintuitive result that there is an optimum metal thickness for minimum planar conductor loss is explored.

A “double delay” de‐embedding algorithm appropriate for electromagnetic analyses is described. This algorithm uses only two standards, a through and a double length through. By evaluating these standards, a special class of port discontinuities may be characterized and removed from the data calculated for a complete structure. Unlike related physical de‐embedding algorithms, both the characteristic impedance and the velocity of propagation of the through lines are determined. The technique described here is difficult to implement in a physical de‐embedding. The de‐embedding theory also provides a new definition of characteristic impedance, “equivalent TEM impedance,” for inhomogeneous media, such as microstrip. This new impedance exhibits a nonmonotonic dispersion which has been measured experimentally but is not seen using previous impedance definitions.