1,721,048 research outputs found
Numerical Green's function technique for the analysis of screens perforated by multiply connected apertures
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Multiple Frequency-Selective Surfaces consisting of ring patches
No full textFrequency selective surfaces composed of planar arrays of ring patches embedded in a stratified dielectric medium are analyzed. The solution of the scattering problem is carried out by the method of moments directly in the spectral domain. In particular, a new set of basis functions with divergent behaviour has been used, and the appropriate trunctation criterion for a stable numerical solution is discussed. Design curves of the resonance frequency and of the reflection bandwidth are shown. Finally, the design of a dichroic plate for a diplexer application in the millimeter wave range is presented
Scattering matrix approach for the design of microwave filters
No full textA synthesis procedure, based on a distributed parameter model, for the design of microwave Biters is presented in this paper. The frequency response of the Biter is described in terms of the characteristic polynomial T(21) = S(11)/S(21) where S(11) and S(21) are the scattering parameters of the filter. Starting from the desired polynomial T(21), the design scheme directly yields the scattering parameters of the various junctions, which can be realized by any kind of discontinuity, The capability of synthesizing an arbitrary frequency response allows one to introduce the concept of a "pre-distorted" characteristic polynomial in order to compensate for the degradations caused by multimodal interactions, frequency dispersion, etc. Comparison with measured data of a Chebyshev-like eight-pole E-plane Biter confirms the validity of the method also in presence of losses
A new approach to the design of dual-mode rectangular waveguide filters with distributed coupling
No full textA synthesis procedure for a new configuration of four-pole dual-mode waveguide filters with distributed coupling is presented, In this configuration the dual-mode coupling is obtained by exploiting the well-known fact that the diagonal polarizations are coupled in an almost square waveguide, The obvious advantage of this type of structure is that the cross sections of all the discontinuities are rectangular, hence the global prediction of the filter is more accurate, The synthesis approach is based on a scattering matrix formulation where the dual-mode coupling is described in terms of a 2 x 2 propagation matrix, Universal design charts, which directly yield the scattering parameters of the various junctions, have been obtained, Comparisons with experimental results of a four-pole filter are also presented
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