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A new circular waveguide loaded with two T-shaped septa and a new triple ridge loaded trough rectangular waveguide are proposed and theoretically analyzed using the Finite Element Method. Numerical results are presented demonstrating that these structures offer a significant increase in both fundamental mode cutoff wavelength and bandwidth when compared to various unloaded and loaded waveguides. © 2002 Wiley Periodicals, Inc. Int J RF and Microwave CAE 12: 190–197, 2002. [ABSTRACT FROM AUTHOR]

A new ridge trough rectangular waveguide loaded with a horizontal “cross” ridge is proposed and analyzed using the finite-element method. Analysis predicts a dramatic increase in the fundamental-mode cutoff wavelength performance and high bandwidth. The waveguide is attractive for emerging microwave and millimeter-wave applications requiring highly integrated, compact structures. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 20–23, 2001. [ABSTRACT FROM AUTHOR]

This paper presents the generalized lowpass filter design method of Levy based on three-dimensional electromagnetic analysis and discontinuity modeling using commercially available full-wave electromagnetic simulators. It shows how to use Levy's method for very accurate theoretical design of a waveguide capacitive iris lowpass filter, using modern 3D EM field-solvers based on the finite element method (FEM), the mode matching method (MM), and the transmission line matrix (TLM) analysis method. This is the first time that design curves and equations, based on full electromagnetic modeling, have been presented for constant thickness capacitive iris filters. We will demonstrate our approach by designing a number of waveguide capacitive iris filters. This paper also demonstrates the generality of the method. This method can be applied to many other types of waveguide lowpass and bandpass filters. © 2000 John Wiley & Sons, Inc. Int J RF and Microwave CAE 10: 190–198, 2000. [ABSTRACT FROM AUTHOR]

This paper presents a systematic approach for computer aided design of waveguide E-plane diplexers. The approach is based on the principle of equireflection three-ports and using the common junction as the constituent elements of the K-inverters of each channel filter. The method divides an E-plane diplexer in a number of key essential building blocks and adopts the best method for the analysis and synthesis of each key block. This has led to a very accurate and efficient design procedure with minimum computation effort. The advantage of the proposed design procedure has been demonstrated by the implementation of several E-plane bifurcated and T-junction millimeter-wave diplexers. The design algorithms presented in this work can be implemented on a low end Pentium machine. An exact design of a diplexer requires no more than 10 min. ©1999 John Wiley & Sons, Inc. Int J RF and Microwave CAE 9: 104–116, 1999 [ABSTRACT FROM AUTHOR]

This paper presents the complete computed aided design approach for the design of H-plane iris-coupled bandpass filters with improved stopband performance. Iris-coupled bandpass filters with mixed (increased and decreased) adjacent resonator widths are proposed for the first time for improvement in the stopband performance. The simulated filter performance shows improved stopband performance and reduced filter dimensions compared with conventional H-plane uniform corrugated waveguide bandpass filters. ©1999 John Wiley & Sons, Inc. Int J RF and Microwave CAE 9: 14–21, 1999. [ABSTRACT FROM AUTHOR]

This paper presents the generalized bandpass filter design method of Levy and Rhodes based on three-dimensional (3D) electromagnetic analysis and discontinuity modeling using commercial software. It shows how to use Levy and Rhodes's famous method for very accurate theoretical designs of waveguide post filters, using modern 3D solvers based on the finite element method, the mode matching method, and the transmission line matrix analysis method. This is the first time that design curves and equations are being presented for constant diameter single and double round rod filters by full electromagnetic modeling. The approach is demonstrated with designs for a number of waveguide round rod filters. This paper also demonstrates the generality of the method. This method can be applied to many other types of coupled resonator waveguide band pass filters. © 1998 John Wiley & Sons, Inc. Int J RF and Microwave CAE 8: 484–497, 1998 [ABSTRACT FROM AUTHOR]

The method of integral equations is used for solving the problem of electromagnetic wave diffraction by an inclined dividing boundary between two dielectric media and by dielectric inserts with such boundaries in rectangular waveguides. Characteristics of the numerical algorithms are described and physical properties of scattered fields are investigated. © 1998 John Wiley & Sons, Inc. Int J RF and Microwave CAE 8: 248–255, 1998. [ABSTRACT FROM AUTHOR]

A coaxial line to a rectangular waveguide junction, backed by an iris-coupled cavity, is analyzed using a new approach based on the five-cavity moment method. The scattering matrix of the junction is obtained by combining the mode-matching method and an interpolation technique. The computed results are checked for orthogonality and unitary conditions, and are verified against experimental results. The proposed structure and the analysis method will be useful in the design of extracted pole filters, diplexers, and multiplexers. © 1998 John Wiley & Sons, Inc. Int J RF and Microwave CAE 8: 20–26, 1998. [ABSTRACT FROM AUTHOR]

In this work a direct synthesis technique is presented for the optimum design of rectangular waveguide continuous and stepped impedance transformers. The synthesis technique is based on a generalized Fourier transform pair and it is implemented on a 486 DX2 machine. Unlike the conventional techniques, the proposed method is exact and does not rely on repeated analysis-based computer optimization that requires a large computer memory and speed. The proposed method requires less than a second to design a Chebyshev EH-plane transformer. The validity of the method has been shown by the design and analysis of several E-, H-, and EH-plane rectangular waveguide Ka-band transformers. The analysis subroutines were verified using published experimental results. [ABSTRACT FROM AUTHOR]

A closed-form dispersion expression for shielded microstrip lines is presented here for the first time. The expression is valid for a wide range of frequencies, geometrical parameters, and substrate dielectric constants. Unlike previous expressions for open microstrip lines, the inflection frequency of the dispersion curve has been chosen to be a quadratic function of the frequency at which the quasi-TEM mode of the microstrip couples strongly with the lowest order transverse electric mode of the equivalent parallel plate waveguide of the microstrip. Because this expression is accurate with respect to numerical techniques, it will be useful in time and frequency domain analyses of various shielded microstrip discontinuities, components, resonators, and VLSI packagings. Dispersion in open microstrip can be treated as a special case of this expression. [ABSTRACT FROM AUTHOR]

Wave propagation along a rectangular dielectric waveguide with slowly varying width has been studied using a transformed coordinate system and an effective cross-section approach. The associated differential equation has been solved using numerical analysis and Hill's analysis. The computed results have been verified using the cascaded transmission line matrix analysis of the structure in the original coordinate system. The agreement is found to be excellent. Many properties of the modulated periodic structure, for example, the propagation constant, the phase and the group velocities, the axial dependence of the E11y mode, and the space harmonic, have been studied. The results and the method will be useful in computer-aided design of dielectric waveguide phase shifters and filters. [ABSTRACT FROM AUTHOR]

Several miniature bandpass filters have been developed by accurate modeling of experimental and computer-generated coupling data of hairpin-line microstrip line resonators on high dielectric constant (εr = 80 and 90) substrate. The materials are temperature stable and of high quality factor. The experimental results show excellent filter shapes and some novelty of the design approach. Besides the experimental results, this article also presents the curves and semiempirical models for the coupling coefficients between hairpin-line resonators for two different dielectric materials and thicknesses. The method and the results will be useful in realizing compact planar filters for cellular radio, global positioning systems and super-conducting microstrip filters. [ABSTRACT FROM AUTHOR]

This article presents a computer-aided synthesis technique for E-plane and iris-coupled waveguide handpass filters. This technique uses fewer optimization variables than are required by the existing techniques. The designer begins with an accurate u priori knowledge of the search direction and uses an efficient penalty, function. The closed-form expressions for waveguide discontinuities, for the initial computation of the K-inverter values in the optimization procedure, greatly enhances the design speed. The technique has been implemented on a personal computer and has been found to be as accurate as the existing methods implemented on mainframe computers. Results are presented for several Ku and Ka-band iris-coupled and E-plane filters. [ABSTRACT FROM AUTHOR]

This article presents the derivation of an analytical equation for the equivalent dielectric constasnt of a microstrip on an anisotropic substrate. Unlike previous methods, this approach does not require the evaluation of Green's function or finite element analysis. The equivalent dielectric constant, together with an empirically derived dispersion equation, predicts the phase velocity to within 1% of the rigorous full-wave solution. The use of the model is demonstrated by the analysis of a rectangular pulse propagation along a 50-Ω microstrip on a Sapphire substrate. [ABSTRACT FROM AUTHOR]

Introduces several articles about the computer-aided design of waveguides.

Comments on the study, "Characteristic Impedance of a Curved Microstrip Transmission Line," by J. S. Roy, D. R. Poddar, A. Mukherjee and S. K. Chowdhury. Discussion on several facts in the study that were allegedly misleading; Problem concerning microstrip technology.