A clever way to simulate numerical matched loads is presented and applied in the mathematical framework of the moment method. This approach presents a lot of advantages with regard to other numerical matched load simulations, and could be used whateier the shape of the planar circuit without the help of the characteristic impedance concept. Results show that very good efficiency is obtained for the reflection coefficient of such matched loads. Typical results are exhibited for S‐parameter determination of multipart microstrip circuits. © 1994 John Wiley & Sons, Inc.

The purpose of this communication is to present an analysis of the ac impedance of superconducting strips for any geometry by derivation of the current distribution over the strip cross section. The analysis is based on the separation of varible teg*nique and the Green's function method. The aim of this study is to obtain an accurate determination of the equivalent surface impedance of superconducting thin films, which may be employed in the simulation of superconducting or regular devices with "resistive sheet-based integral equation techniques". The surface impedance is modified by using weighting factors in order to use equivalent surface impedance concept within spectral domain approach. Typical results are presented.

In this Letter, we propose to show the existence of quasicomplex modes of boxed coplanar lines laid on a lossy dielectric substrate for millimeter‐wave applications, using the method of lines with non‐equidistant discretization. These quasicomplex modes are defined by studying the behavior of the two complex solutions of the propagation problem of the classical lossless boxed coplanar line versus the losses of dielectric substrate. © 1994 John Wiley & Sons, Inc.

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