Aperture matching of a dielectric loaded circular waveguide element array

Lee, J.J.; Chu, Ruey-Shi

doi:10.1109/8.18738

Cited by 14 publications

(9 citation statements)

References 4 publications

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“…In a similar fashion, the th element of the matrix of size is (11) where the integrand fields are from (6) again. The represents the index of the weighting function , which runs through the same indices as those of , being the index of the RWG basis functions.…”

Section: Galerkin Weighting Of Boundary Conditionsmentioning

confidence: 99%

“…But still, to maintain widescan match over a broad frequency range remains difficult, if not unresolved. For open-ended waveguide arrays, other means of matching include the insertion of dielectric sections within the waveguides [10], [11] or placement of dielectric sheath layers over the array aperture, to serve as impedance tuners [12]. Recently, there has been a reported work on a new body of revolution (BOR) type of dual-polarized broad band array element that is able to attain broad scan range over a wide impedance bandwidth [13].…”

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confidence: 99%

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Improved Matching of Waveguide Focal Plane Arrays Using Patch Array Covers as Compared to Conventional Dielectric Sheets

Kehn

Shafai

2009

IEEE Trans. Antennas Propagat.

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This paper presents the advantages of microstrip patch array covers as matching layers for waveguide arrays, as compared with the use of conventional dielectric sheets. It will be demonstrated that both types of covers can be tuned to improve the transmission levels of uncovered arrays at either low frequencies or over a very wide band. However, at low frequencies where the radiation performance tends to be poor due to strong mutual coupling between closely separated elements, the patch array cover offers itself as a lower profile and lighter weight matching structure. This makes it highly advantageous for use in space applications and satellite communications. In addition, it is also able to provide wider matching bandwidths than dielectric sheets. Here, we present a rigorous analysis of such a patch array printed on a dielectric slab and placed over an array of sidewall loaded hard rectangular waveguides. Due to the desirable properties of its aperture field, this type of element serves as an ideal reference for conveying the properties of the two matching layers studied here. Also, to ensure the matching layer performance is independent of the array elements, optimized elements are used in all computations. The method of moments using spectral Green's functions for multilayer structures is employed. Two array operation scenarios are studied, which are the direct radiating phased arrays, and focal plane arrays (FPAs) as feeds for reflectors.Index Terms-Array matching, focal plane array (FPA) feed, hard waveguide array, microstrip patch array, sheath-covered waveguide array.

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Section: Galerkin Weighting Of Boundary Conditionsmentioning

confidence: 99%

mentioning

confidence: 99%

Improved Matching of Waveguide Focal Plane Arrays Using Patch Array Covers as Compared to Conventional Dielectric Sheets

Kehn

Shafai

2009

IEEE Trans. Antennas Propagat.

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“…Crossed dipoles can be realized on the same plane as the feed circuit [1] or on a separate plane on top of the feed circuit [2]. Loading a waveguide aperture with dielectric material has been employed for impedance matching [18] or for radiation pattern improvements [19].…”

Section: Introductionmentioning

confidence: 99%

A New Dual Circularly Polarized Feed Employing a Dielectric Cylinder-Loaded Circular Waveguide Open End Fed by Crossed Dipoles

Bang¹,

Choi²,

Noh³

et al. 2016

International Journal of Antennas and Propagation

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This paper presents a new dual circularly polarized feed that provides good axial ratio over wide angles and low cross-polarized radiation in backward direction. A circular waveguide open end is fed with two orthogonally polarized waves in phase quadrature by a pair of printed crossed dipoles and a compact connectorized quadrature hybrid coupler. The waveguide aperture is loaded with a dielectric cylinder to reduce the cross-polarization beyond 90 degrees off the boresight. The fabricated feed has, at 5.5 GHz, 6.33-dBic copolarized gain, 3-dB beamwidth of 106°, 10-dB beamwidth of 195°, 3-dB axial ratio beamwidth of 215°, maximum cross-polarized gain of −21.4 dBic, and 27-dB port isolation. The reflection coefficient of the feed is less than −10 dB at 4.99–6.09 GHz.

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“…In particular, in the paper [1], this is archived by using the additional matching layer with the smaller permittivity. On the other hand, the useful employment of the special air gap provides a high performance of both the individual radiator and array itself at the frequency range of 1.3GHz [2,3].…”

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confidence: 99%