Search results for "Guide"

Fast and accurate analysis and design of substrate integrated waveguide (SIW) filters

2007

This paper describes the application of the boundary integral-resonant mode expansion (BI-RME) method to the accurate modelling of substrate integrated waveguides (SIW). The new formulation fully exploits the particular geometry of this class of structures, thus providing a very efficient analysis method to be used within CAD tools of SIW filters. The advantages of this method have been proved with the successful design of two filters operating in the microwave and millimeter-wave bands.

EM Based Synthesis and Design of Bandpass Waveguide Filters Including Manufacturing Effects with FEST3D

2011

This article aims at the industry interest on automated design tools that are able to take into account manufacturing effects. First, an efficient design strategy for bandpass waveguide filters including the rounded corners arising from low-cost manufacturing procedures is presented. This technique is based on a recent enhanced prototype and synthesis methodology able to consider the real structure parts. Using the resulting electromagnetic (EM)-based synthesis technique, an excellent structure is extracted, which requires, at most, only a slight final EM optimization. Second, this article presents analytical expressions providing error estimates for the different filter performances in ter…

FDTD signal extrapolation using a finite impulse response neural network model

1999

A New Planar Microstrip Resonator for Microwave Circuits: The Quasi-Fractal Microstrip Resonator

1999

a new shape for microwave planar circuits using the self-similarity of the fractal geometry is presented. This new shape allows the generation of numerous resonant frequencies for this microwave planar resonator due to the surfaces encasilng. The resonant frequency assessment can be useful to concept specific filters or wide frequency band matching loads as examples, without consuming circuit surface.

Performance analysis and comparison of symmetrical and asymmetrical configurations of evanescent mode ridge waveguide filters

2009

[1] In this paper, the trade-offs between out-of-band performance, filter length, power-handling capability, and insertion loss of both symmetrical and asymmetrical evanescent mode ridge rectangular waveguide filters are investigated. As a result, clear design methodologies for optimizing such performances are proposed. The developed methodologies are then applied to design several evanescent mode filters, and a complete performance analysis of the symmetrical and asymmetrical structures is performed. From the performance analysis results, the designer can choose the more appropriate filter topology and design strategy to satisfy the prescribed specifications.

An efficient integral equation technique for the analysis of arbitrarily shaped capacitive waveguide circuits

2011

In this paper a new and efficient integral equation formulation is presented for the analysis of arbitrarily shaped capacitive waveguide devices. The technique benefits from the symmetry of the structure in order to reduce the dimensions of the problem from three to two dimensions. For the first time, this technique formulates the waveguide capacitive discontinuity problem as a 2D scattering problem with oblique incidence, combined with an efficient calculation of the parallel plate Green's functions. Results for a capacitive impedance transformer are successfully compared with measurements for validation of the proposed theory.

Modelling of Laser Operation in RPE Nd3+:LiNbO3 Channel Waveguides

2006

In this work, laser action in RPE Nd3+:LiNbO3 is modelled by using the overlapping integrals method. Different pumping schemes, TE or TM, have been considered in order to reproduce the experimental measurements. Calculated results indicate that the slope efficiency remains basically independent on the pumping scheme while the threshold pump power increases for TE pumping.

Accessibility of the Italian institutional web pages: a survey on the compliance of the Italian public administration web pages to the Stanca Act and…

2014

Accessibility of the Italian public administration web pages is ruled by the Stanca Act and in particular the Decree of the Minister issued on July 8, 2005. In this paper, an objective test is performed on the official web pages of the Italian province and region chief towns to check their compliance to the 22 technical requirements defined by the Stanca Act. A sample of 976 web pages belonging to the websites of the Italian chief towns have been downloaded in the period October---December 2012. Such a data collection has been submitted to Achecker, the worldwide recognized syntax and accessibility validation service. Several accessibility and syntax errors have been found following the aut…

Oncogeriatry: Communication, sharing, coordination of an emerging reality. The IIIrd Official Meeting of the AIOM Working Group on Oncogeriatry

2010

The clinical management of the oncological elderly patient represents one of the most important challenges for today's oncology and, above all, for the future. The number of elderly patients with neoplastic pathologies is destined to increase proportionally to the duration of life and therefore a correct management of their conditions becomes an element of priority from the scientific and economic point of view. Close relationships and collaborations between Oncologist and Geriatrics are definitely desirable to be able to guarantee the best way for a good treatment (specific and of support) of these elderly patients. The components of the AIOM Working Group on Oncogeriatry have gathered the…

Modeling by the finite element method of acoustic radiation in waveguides lined with locally or non locally reacting absorbent materials in the prese…

2011

Our concern in this work is the problem of acoustic propagation in guides lined with locally or non locally reacting materials with the presence of mean fluid flow. In several industrial systems such as aircraft jet engines, mufflers exhaust and ventilation systems, noise is mostly channeled outside by guides of more or less complex geometries. A study of waveguides makes it possible to predict and understand the physical phenomena such as refraction, convection, absorption and wave attenuation. In waveguides studies, guides are often considered infinitely long to get rid of some phenomena (reflection for example) at their ends. Solving the problem of acoustic propagation in infinite guides…