Jan Michael Reiter

Automated design of waveguide components using hybrid mode-matching/numerical EM building-blocks in optimization-oriented CAD frameworks-state of the art and recent advances

Fast hybrid mode-matching/boundary-contour (MM/BC) and mode-matching/finite-element (MM/FE) waveguide building blocks are described for the optimization-oriented use in powerful circuit computer-aided design (CAD) tools and the automated design of waveguide components. The efficient electromagnetic (EM) CAD technique allows the accurate design of a comprehensive class of rectangular and circular waveguide components including realistic structures of higher complexity. The efficiency and flexibility of the hybrid CAD method is demonstrated at advanced EM design examples, such as broad-band circular-to-rectangular waveguide transitions including octagonal cross sections, waveguide resonator filters with rounded corners, optimum-shaped bends, dual-mode filters with coupling sections without tuning screws, ridged waveguide filters with rounded corners, and multiplexers. The designed components are directly amenable to cost-efficient fabrication techniques like computer-controlled milling methods. The theory is verified by available measurements.

Rigorous analysis of arbitrarily shaped H- and E-plane discontinuities in rectangular waveguides by a full-wave boundary contour mode-matching method

A rigorous boundary contour mode-matching (BCMM) method is presented for the efficient calculation of the modal scattering matrix of arbitrarily shaped Hand E-plane discontinuities, junctions, and/or obstacles in rectangular waveguides. For the inhomogeneous waveguide region with general contour, the field is expanded in the complete set of cylindrical wave functions. The full-wave expansion allows the immediate rigorous inclusion of cascaded structures such as combined H- and E-plane bends. The efficiency of the method is demonstrated at the rigorous design of useful waveguide components which could not be modeled by mode-matching technique so far: cylindrical post-compensated H-plane T-junction, mitered H-plane and E-plane bends of arbitrary angle, cascaded H-/E-plane bends, circular post-coupled filter, E-plane filter with rounded corners, 180/spl deg/ rat race structure, and side-coupled dual TE/sub 311//TE/sub 113/-mode filter. The theory is verified by measurements. >

A boundary contour mode-matching method for the rigorous analysis of cascaded arbitrarily shaped H-plane discontinuities in rectangular waveguides

A rigorous boundary contour mode-matching (BCMM) method is presented for the efficient calculation of the modal scattering matrix of cascaded, arbitrarily shaped H-plane discontinuities, junctions and/or obstacles in rectangular waveguides. For the inhomogeneous waveguide region with general contour, the field is expanded in the complete set of cylindrical wave functions. The mode-matching technique is applied at the boundary to the waveguide ports and is shown to yield quick convergence and high numerical stability. Moreover, the modal scattering matrix of the corresponding region is obtained directly. The generalized modal scattering matrix technique achieves the rigorous and flexible modeling of composed H-plane waveguide structures of arbitrary cross-section, including the higher-order mode interactions at all discontinuities, such as of inductive iris coupled filters with resonators of more general shape. The theory is verified by comparison with results obtained by other methods.<<ETX>>

A full-wave boundary contour mode-matching method (BCMM) for the rigorous CAD of single and cascaded optimized H-plane and E-plane bends

A new full-wave boundary contour mode-matching (BCMM) method is presented for the efficient and rigorous calculation of the modal scattering matrix of mitered H-plane and E-plane bends in rectangular waveguides. For the inhomogeneous waveguide region with general contour, the field is expanded in the complete set of cylindrical wave functions. At the boundary to the ports with homogeneous waveguide sections, the mode-matching technique yields the modal scattering matrix of the corresponding key-building block directly. The usefulness of the method is demonstrated at the design of optimum mitered H-plane and E-plane corners, a circular H-plane bend and of a structure of cascaded mitered H- and E-plane corners. The theory is verified by measurements.<<ETX>>

Modal analysis of arbitrarily shaped irises in waveguides by a hybrid contour-integral mode-matching method

A hybrid contour-integral mode-matching (CIMM) technique is presented for the rigorous calculation of the modal scattering parameters of arbitrarily shaped irises in waveguides which combines the advantages of flexibility and high numerical efficiency. The fast contour-integral matching yields the eigenmodes in the iris cross-sections for calculating the generalized scattering matrix of the complete iris discontinuity by the efficient mode-matching technique. This combined method takes arbitrary iris geometries, arbitrary rotation of the iris, and the effects of finite thickness or different waveguide ports rigorously into account. The method is verified by comparison with results calculated by the finite element method.<<ETX>>

Hybrid boundary contour mode-matching analysis of arbitrarily shaped waveguide structures with symmetry of revolution

A combined mode-matching/boundary contour mode-matching (MM/BCMM) technique is described for the rigorous and fast analysis of circular waveguide discontinuities including sections with arbitrarily shaped geometry with symmetry of revolution. The technique involves advantageously the flexibility of both the BCMM method for modeling waveguide regions of more general shape and the efficiency of the proven standard mode-matching (MM) method for circular waveguide step discontinuities. The usefulness of the hybrid method is demonstrated for the design of a spherical two-resonator filter fed by circular waveguides with circular irises. Excellent agreement with reference calculations for circular waveguide tapers verify the accuracy of the proposed method.

Full-wave boundary contour mode-matching analysis and CAD of cavities with partial height post and rounded corners for sophisticated conductor loaded cavity and combline filter designs

The boundary contour mode-matching method (BCMM) is extended to provide the rigorous analysis of cavity T-junctions with interior partial height post and rounded corners. It allows the full-wave CAD of complete combline resonator and conductor loaded TE/sub 101/ mode cavity filter configurations with the suitable implementation of cross couplings for the realisation of arbitrary filter functions. Thus, the approach accounts for the consideration of the particular rounded shapes when using the state-of-the-art CNC milling techniques for the realization of the component. Verification of the method is provided by several designs as, e.g., a single T-junction cavity, a 10resonator combline filter and a 3-pole conductor loaded cavity. Accurate coincidence of computed and measured results of these designs proves the introduced approach.

CAD of waveguide structures with production based radii at arbitrary double (E-H) plane steps and junction ports

The introduction of an enhanced Boundary Contour Mode Matching (BCMM) approach is shown to provide accurate and efficient analysis of waveguide structures with curved shapes at double (E-H) plane discontinuities of junctions and steps. Such geometries take account or the capabilities of state-of-the-art CNC milling production techniques, commonly used for integrated waveguide subsystems. The method is based on direct expansion of the electromagnetic fields of the double-plane discontinuities into the modes of the connecting rectangular waveguides and additionally in case of junctions into cylindrical cavity modes. Validation of the approach has been proven by several component designs, that exhibit almost coincidence of computed and measured responses. The results of a special 4-pole filter design at 10 GHz using bypass couplings for a tailored asymmetric response and a 3 dB E-plane short-slot coupler, operating at 32 GHz, are presented as quite different examples.

Modal analysis of parallel and crossed rectangular waveguide broadwall couplers with apertures of arbitrary shape

Parallel and crossed rectangular waveguide broadwall couplers with apertures of arbitrary shape and number are analyzed rigorously by the efficient and flexible boundary-contour/mode-matching (BCMM) method. The modal S-matrix combination technique takes adequately into account both the finite wall thickness and the higher order mode interaction between the discontinuities. Examples with circular, elliptical, and cross apertures demonstrate the flexibility of the design method. The theory is verified with measurements.