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Approximate formulae for the radial wave numbers of'the surface wave modes in a grounded dielectric structure are presented. These were obtained by using the concept of successive approximation iteration scheme. Numerical results compare well with the actual values of the surface wave number. Received 1-31-90Microwave and Optical Technology Letters. 3/5, 169-172 ABSTRACT A low-cost, easy to fabricate waveguide-to-microstrip E-probe trartsition for the entire X band is introduced. Experimental data shows the E-probe tmnsitiott to be broadband with low insertion loss.The design of a test firture to characterize accurately a single waveguide-to-microstrip transition is also presented.

In the present article we give a general three-dimensional formalism for scattering in two half spaces, one of which contains a bounded inhomogeneity. Our formalism consists of an extension of the transition matrix method which has been given by Waterman, a method which applies equally well to acoustic, electromagnetic, and elastic scattering. The formalism is here developed in detail for the case when the source and inhomogeneity are situated in different half-spaces. However, the same method works for other source positions as well, and the basic equations are given also for the case when the source and the inhomogeneity lie in the same half space. In the final expression for the total scattered field, that part (the so-called anomalous scattered field) which depends on the presence of the inhomogeneity, can be separated, and the physical meaning of the various quantities which determine this anomalous scattered field can be identified. The inhomogeneity enters through its T matrix, and previous results on various bounded configurations of scatterers can therefore be inserted and used in the present formalism. Numerical results are given for inhomogeneities consisting of one or two spheres.

A time-domain method to determine two of the physical parameters L, C, R, and G of a nonuniform transmission line, from the knowledge of the remaining two parameters and the transient response of the line, is presented. The method is based on the recently introduced compact Green functions approach. It is shown that any pair of the parameters can be reconstructed if L and C are considered in terms of the characteristic impedance Z and the wavefront speed c. The impedance is assumed to be continuous along the nonuniform line, but may be discontinuous at the end. It is shown that a discontinuity at the end both simplifies the reconstruction and makes the reconstruction less sensitive to noise. The parameters R and G, which both represent losses, are the most difficult to reconstruct. It is found that reconstructions involving c as well as reconstructions of R and G fail under certain conditions, at certain points along the line. The method is tested numerically for all combinations of parameters, and the failure to determine the parameters at some points is illustrated. The influence of noise is also illustrated. The present method should be useful as a fast analysis tool for time domain reflectometer measurements.