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A general approach for deriving quasi-static equivalent circuits for discontinuities in microstrip lines is presented. The formulation is based upon Galerkin's method applied in the Fourier transform domain. Numerical results are presented for a number of different configurations and compared with data available from other sources.

This paper presents an extension of Vajnshtejn's approach for computing the resonance frequencies and loss factors of Fabry-Perot (FP) resonators at microwave frequencies. Numerical results are presented for FP resonators operated at microwave through millimeter frequency range.

A new semianalytical method has been developed which allows efficient numerical solution for radiation from a flanged waveguide filled with a dielectric material. Some numerical results are presented and compared with other available data.

An accurate and efficient method was developed for computing the resonant frequencies of microstrip resonators. The formulation of the problem was carried out rigorously using the full-wave analysis rather than the quasi-static approximation. The characteristic equation was derived using Galerkin's method applied in the Fourier transform domain. The accuracy of the method has been proven by comparing the numerical results with the experimental data. Numerical data have been provided for the microstrip resonators with different structural parameters. Finally, the results for microstrip resonators have been used for predicting the end effect at the open end of microstrip structures.

Reflection coefficients of various order diffracted waves are calculated for an echelette grating which finds important use as a component of suboptical resonators. The classical optics approach has been found to be inadequate for deriving reliable results for this configuration. Accurate solution of the boundary value problem associated with the echelette grating is derived by a new method. The results are useful for the design of suboptical resonators which use the echelette grating as a coupling mirror to achieve a single wavelength operation.

Dispersion characteristics of shielded microstrip lines are investigated using a new technique. The method utilizes the well-known singular integral equation approach for deriving an alternate form of eigenvalue equation with superior convergence properties. It is shown that accurate numerical results may be obtained from this eigenvalue equation using only a 2x2 matrix equation. In comparison, the conventional formulation of the problem requires the use of matrices that are much larger in size. Aside from the numerical efficiency, the simplicity of the method makes it possible to conveniently extract higher order modal solutions for the propagation constants that affect the high-frequency application of microstrip lines. Even though the derivation of the determinantal equation requires some intricate mathematical manipulations, the user may bypass these completely and use the final eigenvalue equation which is programmable on the computer.

The relative convergence phenomenon that occurs in the numerical solution of the integral equation for the iris discontinuity problem is studied both analytically and numerically. It is shown that the solution for the aperture field can be highly dependent upon the manner in which the kernel and the unknown function are approximated in the process of constructing a matrix equation by the moment method. An analytical explanation is provided for the above phenomenon and the theoretical predictions are verified numerically. Also incIuded is a suggested numerical algorithm for detecting and alleviating the relative convergence behavior for more general problems.

The boundary value problem associated with the open microstrip line structure is formulated in terms of a rigorous, hybird-mode representation. The resulting equations are subsequently transformed, via the application of Galerkin's method in the spectral domain, to yield a characteristic equation for the dispersion properties of the open microstrip line. Numerical results are included for several different structural parameters. These are compared with other available data and with some experimental measurements.

Two methods are investigated for solving the problem of plane-wave diffraction by gratings with sinusoidal profiles. The first is based on an extension of the Rayleigh hypothesis, and the second employs an analytic continuation technique for computing the field in regions in which the Rayleigh hypothesis breaks down. Some numerical results are presented to compare the two methods.

A method of solution for radiation from a flanged waveguide is described. The problem is formulated using generalized mode matching technique [1], appropriate for geometries that include open regions. The resultant equation is solved using an extended version of the Modified Residue Calculus Technique originally developed for application to closed region problems. This technique has several advantages, among which is its numerical efficiency. Some numerical results are included and compared with those reported by others.

This note shows that it is necessary to exercise caution when solving certain boundary value problems using conventional numerical techniques, for instance, the moment method. This is demonstrated by considering the problem of diffraction by a strip grating on a dielectric slab and it is shown that the phenomenon of relative convergence [1],[2] occurs in the process of solution; that is, for a given numerical approximation of the kernel of the integral equation the most accurate solution is obtained for an optimum size, and not for the largest size of the matrix. A guide is provided for choosing this optimum size.

An accurate and numerically efficient method is presented for calculating the charge and potential distributions in the shielded version of a coupled microstrip line. The problem is formulated in terms of a coupled set of equations that are resolved by a method developed recently.

This short paper describes a method for computing the edge capacitance of finite or semi-infinite sections of microstrip transmission lines. The approach is based on Galerkin's method applied in the Fourier-transform domain. It is mathematically simple and requires the inversion of rather small-size matrices.

The problem of computing the dispersion characteristics of shielded microstrip lines is studied using Galerkin's method employed in the Fourier transform domain. Numerical results are compared with other available data and experimental measurements. The dispersion characteristics computed in this paper are also shown to be useful for predicting the end effects of a finite section of microstrip line. Some advantages of the method include simplicity and rapid convergence.

In this work a number of semirigorous and numerical techniques are presented for analyzing the microstrip transmission line configurations. The methods of quasi-TEM as well as hybrid-mode analyses are presented in some detail. A discussion of the higher-order modes in such transmission lines is also included. In addition to analyzing the uniform line configurations, the problem of evaluating the effect of losses, end loading, etc., are examined and methods for handling these problems are discussed.

This letter describes a method for analyzing a class of boundary value problems involving cascaded discontinuities in a waveguide. It is shown that problems involving a pair of junctions can be conveniently formulated in terms of a special type of infinite set of equations which can be attacked by an extension of the modified residue calculus method, previously developed in connection with single discontinuity problems. The principal advantage of this approach is its numerical efficiency.

A new numerical method is developed for the analysis of dispersion characteristics of slot lines. Galerkin's method is applied in the Fourier-transform domain to derive a determinantal equation for the propagation constants. It is shown that accurate numerical results can be obtained with even a 2 × 2 matrix.

A coupling method of a confocal-mirror resonator is described in which a multislit structure on a mirror is partially transmitting energy. The sampling theorem is applied to this structure to determine the slit interval so as to minimise the deformation of a resonant-field distribution.