Full wave optimization is implemented to design a wide band transition from shielded stripline to ridge waveguide.A bandpass ridge waveguide filter, with input/output realized through tapped-in stripline is designed.Using rigorous mode matching technique the generalized scattering matrices of all the building blocks are obtained.Design procedure is described and examples are given to demonstrate the features of the tapped-in coupling structure.The tapped-in structure results in a considerable reduction of the filter's total length compared to the use of two transitions.

This work uses an optimization technique for the frequency response of waveguide filters which is more advantageous than conventional waveguide filter optimization techniques. The method uses only three variables in the penalty function, irrespective of the filter order. It drastically reduces the chance of convergence to a local minimum, computer storage requirements and computation time. Several examples are presented to support the validity of the approach. The approach will be valuable in waveguide multiplexer design and in many other areas of engineering science.

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. (C) 2002 Wiley Periodicals, Inc. Int J RF and Microwave CAE 12: 190-197, 2002.

A bandpass ridge waveguide filter, with input/output realized through tapped-in stripline is designed. Using rigorous mode matching technique the generalized scattering matrices of all the building blocks can be obtained. Design procedure is described and examples are given to demonstrate the features of the proposed coupling structure. The proposed structure shows a considerable reduction of the filter's total length.

This paper uses a new optimization technique for determining the frequency response of waveguide diplexers. The proposed technique is considerably more advantageous than the conventional waveguide filter optimization techniques. The technique uses only six variables in the penalty function irrespective of the orders of the two channel filters. This drastically reduces the chances of convergence to a local minimum as well as the computer storage and processing requirements. Two examples are presented to support the validity of this new technique. This technique will be extremely valuable in designing waveguide multiplexers.

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. (C) 2001 John Wiley & Sons, Inc.

This paper presents detailed finite-element analysis of generalized V- and W-shaped shielded microstrip lines in an anisotropic medium. The computed results show detailed quasistatic characteristics of the effective dielectric constant, characteristic impedance, and conductor loss of the lines. The broadside edge coupled lines are proposed for the first time in this paper. Unlike the previous analysis based on the conformal mapping method, this analysis takes into account the top walls and sidewalls, finite metallization thickness, and dielectric anisotropy. The results presented in this paper will considerable advance microwave-integrated-circuit technology using V- and W-shaped shielded microstrip lines.

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.

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. (C) 1999 John Wiley & Sons, Inc.

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. (C) 1999 John Wiley Be Sons, Inc.

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.

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. (C) 1998 John Wiley & Sons, Inc.

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.

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. (C) 1997 John Wiley & Sons, Inc.

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-K (K=80 to 90) substrates. The materials are temperature-stable and of high quality factor. The method discussed is useful for realizing planar filters for cellular radio and global positioning systems, and superconducting microstrip filters.< >

This article presents a computer-aided synthesis technique for E-plane and iris-coupled waveguide bandpass filters. This technique uses fewer optimization variables than are required by the existing techniques. The designer begins with an accurate a 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.

The scattering parameters of a step discontinuity in a microstrip line, on an uniaxially anisotropic substrate, has been analyzed using the mode matching technique. Closed-form equations for the dispersion of the effective dielectric constant and the effective width of the planar waveguide model of microstrip on an anisotropic substrate have been used. Computed data are presented for a number of commercially available anisotropic substrates, for different cutting angles

This article presents the derivation of an analytical equation for the equivalent dielectric constant 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 regorous full-wave solution. The use of the model is demonstrated by the analysis of a rectangular pulse propagation along a 50-OMEGA microstrip on a Sapphire substrate.