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

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Mohammad Asif Zaman ◽  
Md. Abdul Matin
Keyword(s):  
Differential Geometry ◽  
Geometrical Optics ◽  
New Method ◽  
Geometrical Theory ◽  
Uniform Illumination ◽  
Reflector Antennas ◽  
Reflector Surface ◽  
Reflector System ◽  
Geometrical Theory Of Diffraction ◽  
Main Reflector

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.

scholarly journals Analysis of Arbitrary Reflector Antennas Applying the Geometrical Theory of Diffraction Together with the Master Points Technique

2013 ◽  
Vol 2013 ◽  
pp. 1-13
Author(s):  
María Jesús Algar ◽  
Jose-Ramón Almagro ◽  
Javier Moreno ◽  
Lorena Lozano ◽  
Felipe Cátedra
Keyword(s):  
Method Of Moments ◽  
Near Field ◽  
Complex Geometries ◽  
Geometrical Theory ◽  
Reflector Antennas ◽  
New Approach ◽  
Sampling Points ◽  
Time Requirements ◽  
Geometrical Theory Of Diffraction ◽  
A New Technique

An efficient approach for the analysis of surface conformed reflector antennas fed arbitrarily is presented. The near field in a large number of sampling points in the aperture of the reflector is obtained applying the Geometrical Theory of Diffraction (GTD). A new technique named Master Points has been developed to reduce the complexity of the ray-tracing computations. The combination of both GTD and Master Points reduces the time requirements of this kind of analysis. To validate the new approach, several reflectors and the effects on the radiation pattern caused by shifting the feed and introducing different obstacles have been considered concerning both simple and complex geometries. The results of these analyses have been compared with the Method of Moments (MoM) results.

The effect of loading Gregorian antennas on side-lobe levels

1996 ◽  
Vol 74 (9-10) ◽  
pp. 685-691
Author(s):  
Erkan Afacan ◽  
Erdem Yazgan
Keyword(s):  
Side Lobe ◽  
Far Field ◽  
Geometrical Theory ◽  
Axially Symmetric ◽  
Radiation Patterns ◽  
Field Radiation ◽  
Geometrical Theory Of Diffraction ◽  
Main Reflector

E- and H -plane radiation patterns of focus-fed, axially symmetric Gregorian antennas are analyzed using the generalized method of the geometrical theory of diffraction. Only the rim of the main reflector was loaded, in a smoothly tapered manner, but the whole surface of the subreflector was loaded. Loads are defined in terms of surface impedances. With the help of this analysis, the effect of the smoothly tapered rim loading on the far-field radiation patterns of Gregorian antennas can be studied in detail.

scholarly journals Bessel Beam Diffraction by an Aperture in an Opaque Screen

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Husnu Deniz Basdemir
Keyword(s):  
Bessel Beam ◽  
Geometrical Optics ◽  
Circular Aperture ◽  
Geometrical Theory ◽  
Scattering Process ◽  
Opaque Screen ◽  
Geometrical Theory Of Diffraction ◽  
Scattered Fields ◽  
Beam Diffraction

The scattering of the Bessel beam by a circular aperture in an opaque screen is investigated by the geometrical theory of diffraction approach. The geometrical optics and diffracted and scattered fields are obtained. The effect of the aperture to the scattering process is analyzed. The uniform versions of field expressions are derived. The geometrical optics and diffracted and scattered fields are examined numerically.

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