Accurate consideration of metal losses at waveguide junctions using admittance and impedance integral equation formulations

[1] At higher frequencies, metal loss effects in passive waveguide components become more pronounced and hazardous. In this paper, we propose two integral equation techniques, based on the generalized admittance and impedance matrices, for the accurate consideration of losses in the metal walls of waveguide junctions. Both techniques have been evaluated in terms of accuracy and numerical efficiency, and conclusions are drawn regarding the best properties of the admittance parameter formulation. Finally, combining such technique with a classical perturbative method for considering propagation losses, we have successfully predicted all loss effects in two real waveguide filters used for comme…

Evaluation of time domain electromagnetic fields radiated by constant velocity moving particles traveling along an arbitrarily shaped cross-section waveguide using frequency domain Green's functions

[1] A technique for the accurate computation of the time domain electromagnetic fields radiated by a charged distribution traveling along an arbitrarily shaped waveguide region is presented. Based on the transformation (by means of the standard Fourier analysis) of the time-varying current density of the analyzed problem to the frequency domain, the resulting equivalent current is further convolved with the dyadic electric and magnetic Green’s functions. Moreover, we show that only the evaluation of the transverse magnetic modes of the structure is required for the calculation of fields radiated by particles traveling in the axial direction. Finally, frequency domain electric and magnetic f…

Efficient Design of Waveguide Manifold Multiplexers Based on Low-Order EM Distributed Models

In this paper, a new systematic technique to design manifold-coupled multiplexers in waveguide technology is proposed. The new technique uses generalized low-order electromagnetic (EM) distributed models, which constitute a half-way point between the fast, but imprecise, analytical models, and the more accurate, but costly, full-wave EM models. The method can be applied to contiguous and noncontiguous channel multiplexers, in both E-plane or H-plane configurations. This paper covers the complete design procedure for manifold multiplexers, starting from the required specifications and finishing with the physical dimensions. After explaining the general design technique for multiplexers with …

Computer-aided design of substrate integrated waveguide filters for microwave and millimeter-wave applications

In this paper, a Computer-Aided Design (CAD) tool of Substrate Integrated Waveguide (SIW) filters for high frequency applications is described. Some synthesis techniques are successfully combined with a fast and accurate full-wave analysis method, thus designing several practical examples of in-line and cross-coupled SIW filters. Prototypes have been manufactured and measured showing good results for different filter topologies. A novel zigzag coupling scheme is proposed for SIW compact filters in order to achieve very restrictive specifications of ultra-wideband (UWB) systems.

Efficient Pole Expansion of the Generalized Impedance Matrix Representation for Planar Waveguide Junctions

This paper proposes a novel pole expansion of the generalized impedance matrix representation for planar waveguide junctions. Proceeding in this way, we have obtained a very efficient algorithm for the accurate wide-band modelling of such junctions, since the most expensive computations are performed outside the frequency loop. For verification purposes, several practical examples are shown in order to prove the numerical efficiency and accuracy provided by this new technique.

Efficient analysis of waveguide filters by the integral equation technique and the BI-RME method

This paper presents the study of rectangular waveguide filters with rounded corners in the cross-section of the waveguides. These components are suitable for low-cost mass production and can be rigorously analyzed by efficient CAD tools. The analysis approach described in this paper is based on the integral equation technique in conjunction with the boundary integral-resonant mode expansion method. Two representative examples are also reported.

Efficient analysis of general waveguide multi-port junctions using a segmentation technique and hybrid matrix formulations

Dans cet article on propose une technique de segmentation basee sur des representations matricielles hybrides (impedance et admitance) pour ľanalyse efficace et exacte de jonctions multi-port de guides ľondes rectangulaires aux ports de forme arbitraire. La technique est expliqee en detail et ľon en deduit une nouvelle methode pour resoudre la connection de matrices hybrides sans inversions intermediaires. Pour valider la theorie, on compare les resultats obtenus avec une jonction T-magique et avec une jonction a six ports avec des donnees experimentales de la litterature. La nouvelle methode proposee est aussi employee avec succes pour resoudre des jonctions T des plans E et H ayant des co…

New distributed model for synthesis of classical dual mode filters

Up to now, distributed models for classical dual mode filters have not been developed. In this paper, the whole procedure to derive such distributed models is shown step by step. The resulting formulas are very similar to those standard ones used for in-line filters since the 1960s. Model limitations, very similar to those related to classical formulas, in terms of precision and bandwidth, are pointed out. Finally, two practical examples of distributed models of dual mode filters for satellite transponders with different orders have been extracted.

Efficient and Accurate Consideration of Ohmic Losses in Waveguide Diplexers and Multiplexers

The accurate consideration of all ohmic losses effects in waveguide manifold diplexers and multiplexers is rigorously studied in this paper. For such purposes, a full-wave CAD tool based exclusively on modal methods is originally proposed. Proceeding in this very efficient way, losses are precisely considered in all common components of such complex devices, i.e. planar junctions, uniform lines and multi-port circuits implemented in waveguide technology. For verification purposes, we have successfully compared our results for a magic-T junction and a manifold diplexer with experimental and numerical results.

Efficient analysis of cubic junction of rectangular waveguides using admittance-matrix representation

In the paper an efficient and accurate method, based on the multimode-admittance-matrix representation and the theory of cavities, is proposed for the analysis of a six-port ‘cubic’ junction composed of the orthogonal intersection of three rectangular waveguides. Very simple closed-form analytical expressions are explicitly detailed for all matrix elements of this basic key building block. More general waveguide multiport junctions, composed of a central cubic junction with arbitrarily shaped waveguide access ports, are also studied using a segmentation procedure. To validate the theory, numerical results are first discussed for a standard rectangular waveguide six-port cross junction. Fina…

High selective H-plane TE dual mode cavity filter design by using nonresonating nodes

The design of H-plane TE dual mode cavity filters using models containing nonresonating nodes is presented. From the models a coupling matrix is derived and decomposed into submatrices, each representing a subcircuit. The optimization and cascading of subcircuits represents a good starting point for the global optimization. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:161–166, 2014

Efficient analysis of in-line waveguide filters and frequency-selective surfaces with stepped holes

This paper presents a novel method for the analysis of large classes of microwave and mm-wave passive components, including in-line waveguide filters, single- and multi-layer frequency selective surfaces, and open-ended waveguide array antennas. This method is based on the segmentation technique, which permits us to reduce complex components to cascaded waveguide step discontinuities, which are separately characterized through their generalized impedance matrices, as calculated by the integral equation (IE) technique and the boundary integral-resonant mode expansion (BI-RME) method. Some examples demonstrate the flexibility and efficiency of the IE/BI-RME method, and its utility in investig…

Compensation of the impact of low-cost manufacturing techniques in the design of E-plane multiport waveguide junctions

In this work, a full-wave tool for the accurate analysis and design of compensated E-plane multiport junctions is proposed. The implemented tool is capable of evaluating the undesired effects related to the use of low-cost manufacturing techniques, which are mostly due to the introduction of rounded corners in the cross section of the rectangular waveguides of the device. The obtained results show that, although stringent mechanical effects are imposed, it is possible to compensate for the impact of the cited low-cost manufacturing techniques by redesigning the matching elements considered in the original device. Several new designs concerning a great variety of E-plane components (such as …

Design of compensated multiport waveguide junctions considering mechanization effects

Abstract A new tool for the rigorous and efficient design of compensated multiport waveguide junctions, considering the mechanization effects due to low-cost manufacture techniques, is presented. Several new designs for a great variety of key components, present in modern microwave and millimetre-wave equipment, are proposed taking into account the introduction of rounded corners in the rectangular waveguide access ports. The new implemented tool permits to control and compensate for the potential degradation of the wide-band performance of such components prior to their fabrication, thus achieving an optimal design. All the presented results have been successfully validated by comparing th…

Efficient boundary integral-resonant mode expansion method implementation for full-wave analysis of passive devices based on circular waveguides with arbitrary perturbations

In this study, the efficient full-wave analysis of passive devices composed of circular and arbitrarily-shaped waveguides is considered. For this purpose, the well-known boundary integral-resonant mode expansion (BI RME) method has been properly extended. Circular waveguides are used for resonant mode expansion, whereas the arbitrary contour is defined by any combination of straight, circular and elliptical segments, thus allowing the exact representation of the most widely used geometries. The proposed algorithm extends previous implementations of the BI RME method based on circular waveguides by considering circular and elliptical arcs for defining arbitrary geometries. Similarly, it allo…

On the Rigorous Calculation of All Ohmic Losses in Rectangular Waveguide Multi-Port Junctions

In this paper, all ohmic losses effects present in rectangular waveguide multi-port junctions are rigorous and efficiently computed. For this purpose, a new formulation based on the theory of cavities, which provides generalized admittance matrix representations for such junctions, is proposed. To validate this theory, we have successfully compared our results with numerical data of a lossy E-plane T-junction and of a hollow waveguide, as well as with experimental measurements of a real H-plane T-junction.

A rigorous and efficient full-wave analysis of uniform bends in rectangular waveguide under arbitrary incidence

In this paper, a rigorous full-wave analysis of uniform bends in rectangular waveguides is performed. An accurate and efficient method-of-moments solution combined with the generalized-admittance-matrix (GAM) formulation is proposed in order to achieve a full-wave characterization of the analyzed structures. This full-wave modal solution turns out to be necessary for modeling complex microwave devices involving an arbitrary number of discontinuities between curved and straight waveguides, where all the modes of the involved guides are excited. The key feature of the presented method lies in the GAM representation of single and cascaded curved E- and H-plane uniform bends, which allows the c…

CAD of complex passive devices composed of arbitrarily shaped waveguides using Nyström and BI-RME methods

In this paper, a novel computer-aided design (CAD) tool of complex passive microwave devices in waveguide technology is proposed. Such a tool is based on a very efficient integral-equation analysis technique that provides a full-wave characterization of discontinuities between arbitrarily shaped waveguides defined by linear, circular, and/or elliptical arcs. For solving the modal analysis of such arbitrary waveguides, a modified version of the well-known boundary integral-resonant-mode expansion (BI-RME) method using the Nyström approach, instead of the traditional Galerkin version of the method of moments, is proposed, thus providing significant savings on computational costs and implement…

Corrigendum to “Design of compensated multiport waveguide junctions considering mechanization effects” [AEUE – Int J Electron Commun, 69 (1) (2015), 328–331]