1,721,045 research outputs found
Mode Matching Analysis of Waveguide Components Exploiting the Variational Meshless Method
No full textThis letter presents the analysis of waveguide components comprising a cascade of step junctions by mode matching in conjunction with the variational meshless method (VMM). In particular, a large number of modal fields of the waveguides are calculated very efficiently by the VMM. Moreover, the collocation points are randomly distributed in each waveguide cross section, and the coupling coefficients are obtained regardless of their mutual distribution. The presented technique is validated through the analysis of two junctions reported in the literature and by comparison with an finite element method (FEM) full-wave software
Exploiting Symmetries in the Variational Meshless Method for 3-D Inhomogeneous Cavities
No full textThe variational meshless method (VMM) is a novel numerical algorithm that combines the intrinsic advantages of the meshless method based on the use of radial basis functions (RBFs) with the reliability of the variational formulation of electromagnetic boundary problems. It has been originally proposed and demonstrated in the analysis of 2-D structures, both homogeneous and inhomogeneous, aiming at the determination of the mode spectrum and the dispersion diagram. In this article, the VMM is extended to the calculation of the resonant modes of 3-D inhomogeneous cavities. The full theory is presented with implementation details. Moreover, the exploitation of symmetries is also discussed, which significantly speedup the method. Some examples are reported, and the results of the VMM are compared against either analytical values (when available) or commercial numerical codes based on the finite element method (FEM). In all cases, the VMM provides a large number of resonant modes with a limited number of unknowns, exhibiting high accuracy in short computing time
Comparative Study on the Design of Dichroic Mirrors for the Upgrade to the K-band uplink channel for the ESA Deep Space Antennas
No full textModified quarter-mode substrate integrated waveguides cavities: Performance study and application to filters
No full textQuarter-mode cavity resonators in substrate integrated waveguide (SIW) technology represent a good solution for the design of compact filters. However, their advantage in terms of reduced footprint is counterbalanced by possible radiation leakage, which may jeopardize the overall performance. This article presents a systematic investigation of the different contributions of losses in quarter-mode SIW (QMSIW) cavities, considering both the standard topology and modified configurations. General guidelines for the choice of the optimal dielectric permittivity and substrate thickness are derived. Experimental results of individual cavity resonators are presented to validate the simulations. Moreover, the design and the experimental verification of a four-pole filter based on classical and modified QMSIW cavities are reported, to illustrate a possible strategy for performance improvement
Using a 3D-Printed Waveguide Filter with Ridge Resonators as a Dielectric Permittivity Sensor
No full textSubstrate Integrated Waveguide (SIW) Cavity Resonators: a Review of Technologies and Applications
No full textThis paper presents an overview of recent advances in substrate integrated waveguide (SIW) technology, with particular emphasis on different topologies and applications of SIW cavity resonators. While cavity resonators are the basic element of several RF and microwave components, SIW cavities can be implemented in a variety of ways, to optimize a given performance. This work outlines miniaturized cavities aiming at the footprint reduction, partially air-filled cavities for the implementation of SIW filters with additional transmission zeros, SIW cavities used as resonant coupling elements in the design of filters, and finally SIW cavities adopted for sensing purposes. For all these structures, a brief description of the operation principle is provided, along with the experimental verification
Substrate Integrated Waveguide Filters with Stacked Cavities
No full textIn this paper the strategy for obtaining substrate integrated waveguide filters for easy manufacturing is illustrated and discussed. The basic idea is to obtain a multilayer filter where just thru-hole vias are used, thus making easier the manufacturing process. This is obtained by designing the filter with identical cavities where evanescent SIW sections are exploited. Furthermore, it is also shown that evanescent cavities can be exploited for the tuning of cavity resonance frequencies
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