Zoran Maricevic

Analysis of a wide radiating slot in the ground plane of a microstrip line

An analysis of a wide rectangular radiating slot excited by a microstrip line is described. Coupled integral equations are formulated to find the electric current distribution on the feed line and the electric field in the aperture. The solution is based on the method of moments and using the space domain Sommerfeld-type Greens function. The information about the input impedance or reflection coefficient is extracted from the electric current distribution on the microstrip line utilizing the matrix pencil technique. The theoretical analysis is described and data are presented and compared with other theoretical and experimental results. >

Time-domain measurements with the Hewlett-Packard network analyzer HP 8510 using the matrix pencil method

The generalized pencil of function (GPOF) method, also known as the matrix pencil method, is used to improve the resolution of HP 8510B network analyzer data in the time domain. This method provides for much higher resolution than the Fourier techniques. A comparison of the two methods is given for the example of the Beatty standard. The examples show that a parametric technique such as the GPOF can provide accurate and reliable results with a high degree of resolution even when the fast Fourier transform (FFT)-based technique fails. >

Dynamic analysis of a microstrip line over a perforated ground plane

A full wave analysis is presented to compute the characteristic impedance and propagation constant of a microstrip line over a perforated ground plane. The perforations in the ground plane are modeled by equivalent magnetic currents. The method of moments is applied to solve the coupled integral equations for the unknown electric current on the microstrip line and the unknown magnetic currents in the apertures. The fields are formulated using the space domain Sommerfeld type Greens functions. The matrix pencil technique is used to obtain the amplitude and the propagation constant of the fundamental modes for both current and the voltage on the microstrip line. Typical numerical results are given. >

Evaluation of excess inductance and capacitance of microstrip junctions

Excess inductance and capacitance of various microstrip discontinuities (bends, impedance steps, and simple vias) are evaluated. For the inductance calculations, the structure is assumed to consist of perfectly conducting foils located in vacuum above a perfectly conducting ground plane. For the capacitance calculations, the structure is assumed to be embedded in a multilayered dielectric medium. The surface-current distribution for the excess inductance calculation and the surface-charge distribution for the capacitance calculation are evaluated numerically solving integral equations based on the boundary conditions. Thereby, the conductor and dielectric surfaces are divided into a number of triangles, and the point-matching technique is used. >

On a class of low-reflection transmission-line quasi-Gaussian low-pass filters and their lumped-element approximations

Gaussian-like filters are frequently used in digital signal transmission. Usually, these filters are made of lumped inductors and capacitors. In the stopband, these filters exhibit a high reflection, which can create unwanted signal interference. To prevent that, a new low-reflection ladder network is introduced that consist of resistors, inductors, and capacitors. The network models fictitious transmission lines with Gaussian-like amplitude characteristics. Starting from the analysis of this network, a procedure is developed for synthesis of a new class of lumped-element RLC filters. These filters have transmission coefficients similar to the classical Bessel filters. In contrast to the Bessel filters, the new filters exhibit a low reflection both in the stopband and passband, they have a small span of element parameters, and they are easy for manufacturing and tuning.

Space domain approach for the analysis of printed circuits

A numerical approach to the solution of printed circuit structures of arbitrary shapes, embedded in a single or multilayer dielectric medium is presented. The electromagnetic fields are described in terms of the classical Sommerfeld integrals. The method of moments has been used to solve the derived integral equations for the surface electric and magnetic currents flowing on the conductors and/or the electric field distribution across the apertures. The matrix pencil technique is employed to decompose the current or the voltage waves along the line into their components like the fundamental modes, higher order modes, etc. The finite structures including discontinuities like bends, T junctions, crossovers, etc. are solved for their scattering parameters utilizing this method. The main advantage of this method is the generality which allows a large variety of problems to be covered. >

Characterization of power loss from discontinuities in guided structures

This paper is an extension of the work presented by Sarkar et al. (1996). In that work it was shown how to utilize the matrix pencil approach to extract S-parameters of N-port microwave structures. In this paper this earlier approach has been extended to analyze radiation/power loss from the discontinuities of guided structures. Specifically, computed results are presented for the S-parameters of an open ended rectangular waveguide radiating into free space along with experimental results given by Marcuvitz (1951). In addition power loss from rectangular and mitered bends are computed for a microstrip line. The present results are more accurate than what is available in the published literature.

Application of matrix pencil technique to analysis of microstrip

We solve for surface current distribution on microstrip patches of arbitrary shape by the method of moments in conjunction with triangular basis functions and Sommerfeld integrals. The matrix pencil method is used to decompose current along the feed and terminating lines into forward and backward traveling waves, yielding scattering parameters of the device. This approach is tested on various examples and its results are compared to both previously published data and measurements performed in the Microwave Laboratory of the Department of Electrical and Computer Engineering at Syracuse University.

An Accurate Method for the Computation of Radiated Power from Discontinuities in Waveguiding Structures

In [1] it was shown how to utilize the Matrix Pencil approach [2]-[3] to extract S parameters of printed circuits. This paper extends the method to the computation of the power radiated from discontinuities in waveguiding structures. Several examples have been analyzed. The first one is an open ended rectangular waveguide radiating into free space. Results agree with the experimental ones given in [4]. Results of other two examples (a microstrip line with rectangular and mitered bends, respectively) are also presented; they also agree with experimental results. This approach haves a number of advantages (listed in the introduction) with respect to other methods and allows accurate design of a wide variety of microwave devices.