GTD analysis of the radiation patterns of a shaped subreflector

Narasimhan, M. S.; Ramanujam, P.; Raghavan, K.

doi:10.1109/tap.1981.1142662

Cited by 3 publications

(7 citation statements)

References 8 publications

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“…The shape of the surface depends on the expression of (⋅). Through literature review, it is found that shaped hyperboloidal subreflectors are usually different from unshaped hyperboloids near the edges [13]. The shaped surface curves towards the vertex at the edges.…”

Section: Surface Equationsmentioning

confidence: 99%

“…However, it is necessary to establish that practical shaped subreflector surfaces can be accurately represented by these equations. Practical data of a shaped hyperboloidal and subreflector surfaces are taken from literature [13]. The dimensions are normalized with respect to subreflector diameter in [13].…”

Section: Surface Equationsmentioning

confidence: 99%

“…Practical data of a shaped hyperboloidal and subreflector surfaces are taken from literature [13]. The dimensions are normalized with respect to subreflector diameter in [13]. By adjusting the distortion parameters in (8) and using them in (7), a surface closely resembling the shaped subreflector surface of [13] is generated.…”

Section: Surface Equationsmentioning

confidence: 99%

“…The dimensions are normalized with respect to subreflector diameter in [13]. By adjusting the distortion parameters in (8) and using them in (7), a surface closely resembling the shaped subreflector surface of [13] is generated. The results are shown in Figure 4.…”

Section: Surface Equationsmentioning

confidence: 99%

“…The shaped subreflector surfaces are assumed to be distorted forms of unshaped surfaces. As most shaped subreflectors resemble their unshaped counterparts [11][12][13], the assumption is logical. The shaped surfaces can therefore be represented by modified versions of the equations that represent the conventional unshaped surfaces.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

A New Method of Designing Circularly Symmetric Shaped Dual Reflector Antennas Using Distorted Conics

Zaman

Matin

2014

International Journal of Microwave Science and Technology

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A new method of designing circularly symmetric shaped dual reflector antennas using distorted conics is presented. The surface of the shaped subreflector is expressed using a new set of equations employing differential geometry. The proposed equations require only a small number of parameters to accurately describe practical shaped subreflector surfaces. A geometrical optics (GO) based method is used to synthesize the shaped main reflector surface corresponding to the shaped subreflector. Using the proposed method, a shaped Cassegrain dual reflector system is designed. The field scattered from the subreflector is calculated using uniform geometrical theory of diffraction (UTD). Finally, a numerical example is provided showing how a shaped subreflector produces more uniform illumination over the main reflector aperture compared to an unshaped subreflector.

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Section: Surface Equationsmentioning

confidence: 99%

Section: Surface Equationsmentioning

confidence: 99%

Section: Surface Equationsmentioning

confidence: 99%

Section: Surface Equationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A New Method of Designing Circularly Symmetric Shaped Dual Reflector Antennas Using Distorted Conics

Zaman

Matin

2014

International Journal of Microwave Science and Technology

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Comments on "Wide-band diffraction improved dual-shaped reflectors"

Ramanujam

James²,

Thomas³

et al. 1983

IEEE Trans. Antennas Propagat.

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Analysis of Electrically Small Hyperbolic Subreflectors Utilizing the Geometrical Theory of Diffraction

Christodoulou

Cook²

1993

Journal of Electromagnetic Waves and Applications

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Cassegrain antennas have been utilized in applications where small size is critical. It has been observed that for antennas having subreflectors of the order of only several λ in diameter, near-in sidelobe levels rise beyond normally predicted values. Eplane sidelobes are often several dB higher than those in the H-plane. Disturbances in the illumination of the primary reflector due to diffraction limitations of the electrically small subreflector are a possible cause of the sidelobe phenomenon. In this work, the results for 3 to 8 λ -diameter hyperboloidal subreflectors, using the geometrical theory of diffraction (GTD) are presented and compared with the physical optics approach and other data. Degradation of the scatter patterns are observed as the subreflector size is decreased, and the differences in the E-and H-plane phase and amplitude patterns are observed in the GTD solution.

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GTD analysis of the radiation patterns of a shaped subreflector

Cited by 3 publications

References 8 publications

A New Method of Designing Circularly Symmetric Shaped Dual Reflector Antennas Using Distorted Conics

A New Method of Designing Circularly Symmetric Shaped Dual Reflector Antennas Using Distorted Conics

Comments on "Wide-band diffraction improved dual-shaped reflectors"

Analysis of Electrically Small Hyperbolic Subreflectors Utilizing the Geometrical Theory of Diffraction

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