Using a feed array it is easy to generate multiple shaped beams, using a. Parabolic dish antennas can provide extremely high gains. The corner reflector antenna, is illustrated in figure 12. These antennas are widely used for radio and wireless applications. In this paper, an analysis is made of the variation of antennas performances under different employment conditions by applying the response surface method and.
An approximation mathematical formula of pattern analysis for distorted reflector antennas considering surface normal vector variation international journal of antennas and propagation, vol. Reflector antennas confine most of the electromagnetic energy captured over their apertures into a focal plane or redirect the radiated field of the feed into far field. Analysis of aperture illumination and edge rolling effects. Calculations of radiation characteristics of reflector antennas with.
Actual reflector antenna always has a deformation which has a serious influence on antenna performance. Pattern analysis for distorted reflector antennas considering surface normal vector variation shuxinzhang,guigengyang,andyiqunzhang key laboratory of electronic equipment structure design, ministry of education, xidian university, xi an, china correspondence should be addressed to yiqun zhang. On distorted surface analysis and multidisciplinary. Reflector antennas utilize curvatures called conic sections. Goldsmith, analysis of active surface reflector antenna for a large millimeter wave radio telescope, ieee transactions on antennas and propagation, 422 1994 176183. A novel method for fitting the distorted reflector of a. An approximation mathematical formula of pattern analysis for distorted reflector antennas considering surface normal vector variation shuxin zhang, 1 guigeng yang, 1 and yiqun zhang 1 1 key laboratory of electronic equipment structure design, ministry of. The large reflector antenna structural design is a typical multidisciplinary design mainly involving structural mechanics and electromagnetics. The arm, which is an accurate and stable analyticalnumerical method, is used for the 2d analysis of epolarized electromagnetic waves scattering from the reflector metal plate with finite thickness.
The main goal of this work is to improve the radiation pattern of the. Effect of the random error on the radiation characteristic of. This paperpresents a concise history of reflector antenna developments over an extended time span. Analysis of reflector antennas provides information pertinent to the analysis of reflector antenna systems. Inducedcurrent analysis of reflector antennas how is. The reflector antenna distortion model is built by exploding test results. Luo, radiation analysis of parabolic cylindrical reflector antenna with a rectangular micro strip patch array as feed, ieee international symposium on antennas and propagation digest uv vol. Electromechanical coupled analysis of large broad band. An antenna reflector is a device that reflects electromagnetic waves. Definitions and experimental study on a hypothetical hard. An approximation of pattern analysis for distorted reflector antennas using structuralelectromagnetic coupling model article in ieee transactions on antennas and propagation 619. Contoured beam antennas multiple beam antennas multiband antennas reconfigurable beam antennas hybrid antennas pim, multipaction, test methods conclusions pg. Integrated structural electromagnetic shape control of large. Reflector antennas paraboloidal reflectors antennas useful for radio astronomy at short wavelengths must have collecting areas much larger than the collecting area o4u of an isotropic antenna and much higher angular resolution than a short dipole provides.
Representative examples are provided for different periods that impacted. An adjustment method for active reflector of large highfrequency antennas considering gain and boresight to cite this article. The main goal of this work is to improve the radiation pattern of the dish antennas by decreasing the side and back lobe levels. A study on reflector antennas and design of reflector antenna. Organized into four chapters, this book begins with an overview of the history of focusing reflector antenna systems characterized by a highly variable. The radiation characteristics of a kind of distorted shaped reflector antenna are computed by using po and ptd method. Reflector systems are probably the most widely used highgain antennas. An approximation mathematical formula of pattern analysis for distorted reflector antennas considering surface normal vector variation by shuxin zhang, guigeng yang and yiqun zhang no static citation data no static citation data cite.
The corner reflector antenna shown below utilizes a reflector formed by two plates. We present analytical expressions for the evaluation of the antenna efficiency loss due to the gravity distortion on large reflector antennas from 6 to 35 m diameter at x and ka bands with a lack of usual complexity. Establishing the equation of the distorted reflector surface is important for calculating antenna performance and precise control. Research article an approximation mathematical formula of. The feed antenna at the reflectors focus is typically a lowgain type such as a halfwave dipole or more often a small. Twostep structural design of mesh antennas for high beam. Hence, the gravitational distortion effects will have much more representative. We present analytical expressions for the evaluation of the antenna efficiency loss due to the gravity distortion on large reflector antennas from 6 to 35 m diameter at x and ka bands with a. The highfrequency applicability of reflector antennas is limited by the distortions and the errors on the reflector surface. Steps in diffraction analysis of reflector antennas with prescribed surface distortions. Introduction highgain antennas are required for longdistance radio communications radiorelay links and satellite links, highresolution radars, radioastronomy, etc. Analysis of reflector antennas provides information pertinent to the analysis of reflectorantenna systems.
Distorted reflector antennas aut journal of electrical engineering. Abstractsurface distortions change the radiation character istics of reflector antennas. Distorted reflector fitting the reflector sometimes is not identical to design paraboloid in antenna manufacturing and installing. A new method to determine the discrete distortions on reflector antennas have been presented. Rahmatsamii, effects of deterministic surface distortions on reflector antenna performance, in. The feed antenna at the reflector s focus is typically a lowgain type such as a halfwave dipole or more often a small. Macos provides computationally efficient general raytrace, differential raytrace, and scalardiffraction calculation capabilities.
Inducedcurrent analysis of reflector antennas listed as icara. Analysis of dualreflector antennas with a reflectarray as. Efficient analysis of reflector antennas using grasp erik jorgensen, hanshenrik viskum, stig b. J design and analysis of multiplereflector antennas cwik 12 hpc go analysis mode allows the user to perform geometric optics analysis on a design and prescription these files are converted to a macos input set. They can easily achieve gains of above 30 db for microwave frequencies. In this paper, an analysis is made of the variation of antennas performances under different employment conditions by applying the response surface method and the. By linearizing the difference between the distorted and undistorted far filed patterns a linear system of equations is constructed. A new bestfitting method based on least square method is submitted in this paper.
A new method of designing circularly symmetric shaped dual reflector antennas using distorted conics mohammadasifzamanandmd. The cornerreflector antenna, is illustrated in figure 12. Analytical expressions for the evaluation of gravity. The caliber of the main reflector surface and the auxiliary reflector. Analysis of reflector antennas paperback november 14, 20 by w.
Besides, reflector distortion will occur under various loads, thus causing the displacement of each node of backup structure. Secondorder sensitivity analysis of electromagnetic performance with respect to surface nodal displacements for reflector antennas and its benefits in. Firstly, a comparison of test data and result of the proposed method of the 3. At last the method in this paper is used in a 40m reflect antenna, the result is accord with practice engineering. Effects of deterministic surface distortions on reflector antenna. An approximation mathematical formula of pattern analysis for. Research article a new method of designing circularly. Among many analyticalnumerical diffraction analysis techniques, we can refer to. Subefficiencies in reflector antennas excl blockage. Active feed array compensation for reflector antenna surface. Introduction 2 satellite reflector antennas are often distorted from their idealized shapes once they are placed in orbit. Feasibility study of a synthesis procedure for array feeds to improve radiation performance of large distorted reflector antennas gas.
For better understanding of these antennas, the concept of parabolic reflector has to be discussed. Deformation of the antenna reflector affects antennas electrical characteristics. Analysis of the radiation characteristics of the reflector. Lopezperez abstractwe summarise the mathematical foundation of the holographic method of measuring the re. Using a reflector antenna with a nonparabolic reflector since the shape is usually fixed the use of an array with a rather complex beam forming network and a large number of elements is not justified. Efficient analysis of reflector antennas using grasp. Reflector antennas operate on principles known long ago from. Organized into four chapters, this book begins with an overview of the history of focusing reflectorantenna systems characterized by a highly variable.
Demand for reflector antennas for use in radars, radio astronomy, microwave. Integrated structuralelectromagnetic shape control of cable. A nearfield cassegrain reflector nfcr is an effective way to magnify a small phased array into a much larger aperture antenna for limited scan applications. Based on the physical optics and variational analysis, the firstorder variational. This distortion may be due to thermal gradients, mechanical stresses, damage from launch, or collisions with foreign objects. An approximation mathematical formula of pattern analysis for distorted reflector antennas considering surface normal vector variation shuxin zhang, 1 guigeng yang, 1 and yiqun zhang 1 1 key laboratory of electronic equipment structure design, ministry of education, xidian university, xian 710071, china. A new bestfit method for distorted reflector antenna surface. An approximation of pattern analysis for distorted reflector. Using a feed array it is easy to generate multiple shaped beams, using a shaped reflector this is much more difficult, but.
It is inducedcurrent analysis of reflector antennas. The mathematical formulation is based upon the usecf the lmerrtz reciprocity theorem which convolves the. Traditionally, the pattern analysis of nfcr is based on a plane wave approach. Personnel at virginia tech performing reflector antenna research reflector antenna research at virginia tech 1. Since arrays of dipoles are impractical at wavelengths o m or so, most. As for the distorted reflector antennas, phase error caused by the surface nodal displacement is usually added in the integral to evaluate its effect. The actual antenna in a parabolic antenna, that is, the device that interfaces the transmission line or waveguide containing the radiofrequency energy to free space, is the feed element.
Pdf the idealized shapes of satellite reflector antennas are often distorted once they are placed in. A study on reflector antennas and design of reflector. As for space requirements, circular polarizations are widely used in spaceborne antennas, which usually lead to a beam shift for offset reflectors and influence. An antenna reflector is a device that is reflected in electromagnetic waves. Using functional calculus, radiation integral is analyzed, and the first. A simple tool for design and analysis of multiplereflector. Abdulmatin department of electrical and electronic engineering, bangladesh university of engineering and technology, dhaka, bangladesh correspondence should be addressed to mohammad asif zaman. Different techniques can be used to compensate the degradation of the radiation characteristics if the surface distortion profile is known. A welldesigned reflector surface with high beam pointing accuracy in electromagnetic performance is of practical significance to the space application of cable mesh reflector antennas. As a result, the antenna reflector will not be a smooth surface. Also all the reflected power is in the same phase, because the path length from the source to the reflector and then outwards is the same wherever it is reflected on the surface of the parabola. The frequency range used for the application of parabolic reflector antennas is above 1mhz. Antenna reflectors can exist as a standalone device for redirecting radio frequency rf energy, or can be integrated as part of an antenna assembly. Reflector antennas introduction highgain antennas are required for longdistance radio communications radiorelay links and satellite links, highresolution radars, radioastronomy, etc.
The method is based on the discretization of the reflector surface into triangular patches. A reflector antenna is the most common type of radar antenna, which is. This book provides an understanding of how design data have been and can be derived. Reflector antennas national radio astronomy observatory. Related content bspline surface fitting and simplified gopo analysis of subreflector correction. Sharma, handbook of reflector antennas and feed systems, vol. Hallquist, lsdyna users manual, university of california, lawrence. Different types of antennas with properties their working. Reflector antenna discrete distortion determination.
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