1,721,075 research outputs found
Design of Circularly Polarized Waveguide Slot Linear Arrays
No full textA design procedure for circularly polarized waveguide slot linear arrays is presented. The array element, a circularly polarized radiator, consists of two closely spaced inclined radiating slots. Both the characterization of the isolated element and the evaluation of the mutual coupling between the array elements are performed by using a method of moments procedure. A number of traveling wave arrays with equiphase excitations are designed and then analyzed using a finite element method commercial software. A good circular polarization is achieved, the design goals on the far field pattern are fulfilled and high antenna efficiency can be obtained
Accurate modeling of coupling junctions in dielectric covered waveguide slot arrays
No full textThis paper investigate the near-field interaction between the coupling slot and the radiating ones in a dielectric-covered waveguide slot array environment. This interaction can strongly affect the array aperture distribution and input match, mainly when each radiating guide contains few slots or the slot offsets are small. We propose a full-wave Method of Moments approach, taking also into account the waveguide wall thickness, to evaluate this interaction. The use of entire domain basis functions allows to get a small and well-conditioned linear system. The results presented in this paper show that the coupling due to high-order modes in the region of the junction can significantly modify the radiating slot voltage, mainly when the offset is small, and also the array input match, though to a lesser extent
An Improved Configuration of a Printed Antenna Fed by a Coplanar Waveguide without Spurious Mode
No full textA rigorous analysis of dielectric-covered narrow longitudinal shunt slots with finite wall thickness
No full textThe need for a protective dielectric cover is becoming more relevant in waveguide slot arrays, especially in space applications. The aim of this paper is to describe a rigorous Method of Moment approach to the analysis of a dielectric-covered longitudinal shunt slot, taking into account the effect of the wall thickness. The whole procedure has been devised aiming at a time effective but precise way to compute the slot admittance, tailored to the needs of design procedures for slot arrays. Simulated results are compared with experimental data, resulting in a very good agreement
Accurate characterization of the interaction between coupling slots and waveguide bends in waveguide slot arrays
No full textIn a waveguide slot array, it is sometimes required to introduce bent short-circuit terminations in the feeding network. This significantly affects the behavior of the coupling slots used in this network, with a very large variation in the coupling coefficient with respect to the standard case. A procedure to accurately evaluate the effect of such bends is presented, thus allowing to include them without any loss in the overall design accuracy. It is based on the method of moments, using a magnetic-field integral equation expressed in terms of the vector potential, which appears to be the most efficient way for waveguide problems. The development is aimed at a very effective implementation, which allows to include it in design tools for waveguide slot arrays without increasing the total computational load, and has been assessed through comparison with experimental results
Full-wave analysis of a waveguide printed slot
No full textIn this paper, we propose a new waveguide slot array configuration, in which the slots are printed on a copper-clad substrate. This configuration can be obtained using a printed slot and therefore allows both a simpler realization of a slot array and permits its reuse when the pattern requirement changes. An innovative and highly effective method of moments procedure has been devised. It employs a spectral domain approach for the computation of the internal Green function. Our code has been validated against a commercial finite element method code, and the agreement is highly satisfactory. The code has then been used to obtain the scattering and radiating properties of the proposed printed slot. Such a slot behaves as a shunt admittance, so Elliott's method (1983) can be used to design an array of printed slots
Full-wave analysis of dielectric-covered radiating series slots
No full textThe need for a protective dielectric cover is presently more and more relevant in waveguide slot arrays, especially in space applications. Therefore, the knowledge about waveguide slot arrays radiating into free space must be completed to design dielectric-covered arrays. The aim of this paper is to describe a rigorous method-of-moment approach to the analysis of a dieletric-covered inclined series slot, able to take into account the effect of the wall thickness. The whole procedure has been devised aiming at a time-effective but precise way to compute the slot resistance, tailored to the needs of slot array design procedures. (C) 1999 John Wiley & Sons, Inc
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