74 research outputs found
A synthesis method for combined optimization of multiple antenna parameters and antenna pattern structure
Wide-angle radiation pattern calculation of paraboloidal reflector antennas : a comparative study
EBG enhanced feeds for the improvement of the aperture efficiency of reflector antennas
We describe the use of electromagnetic bandgap (EBG) super-layers to improve the shape of reflectors illumination function. Following an investigation of the leaky wave pole singularities of the EBG Green's function, the shape of the radiation patterns of small apertures in ground planes are optimized. The maximization of the reflector aperture efficiency can be obtained by properly tuning the super layers geometrical parameters. A prototype of such feed has been designed, manufactured and tested. The results indicate that the inclusion of the EBG, increases the aperture efficiency of the feed+reflector system to values higher than 80%, over a 10% bandwidth. These low profile feeds are compatible with printed circuit board and/or integrated technology
Properties of leaky waves supported by grounded dielectric super-layers and implications on the design of reflector feeds
The design strategy that uses dielectric super-layers with neighboring wave-guides closed in matched loads constitutes a worst case scenario as far as the performance enhancement is concerned and finds applicability in radiometric imaging arrays. On the other side the design strategy that uses dielectric super-layers with neighboring wave-guides closed in properly tuned reactive loads can be seen as best case scenario representative of a multi beam system for a telecommunication satellite with independent channels
Domain integral equations for electromagnetic band-gap slab simulations
Trabajo presentado al International Symposium on Electromagnetic Theory, URSI 2004.Electromagnetic band-gap substrates o er advantages regarding cross-coupling in sub-mm range imaging
array applications. Electromagnetic scattering by such substrates may e ectively be formulated in terms of integro-
di erential equations. The scattered elds are evaluated via the spectral domain in which the 3-D problem reduces to
an in nite system of coupled 1-D integro-di erential equations. The associated matrix-vector products are dominated
by FFTs. For moderate frequencies an elementary preconditioner in combination with a prudent initial estimate usually
su ces to reach rapid convergence using the transpose-free quasi-minimal residual method.The research presented above has been financially supported by ESA/ESTEC, under Contract No.
15632/01/NL/JA
Een multi-frequency feedsysteem ten behoeve van propagatie experimenten met de satelliet olympus
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