الفهرس 
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Abstract
The corner reflector is one of the reflectors which dramatically increase the directivity of the feeding element. Designing reflector antennas of Various geometries did not really advance until the days of world war II , when numerous radar applications evolved to satisfy diverse technical demands. Subsequent demands for reflectors for use in radio astronomy , microwave communication , tracking radars, etc., have resultedin both the development of sophisticated reflector configuration and analytical and experimental design techniques. Some of the most popular reflectors are planar or curved surfaces. In this work only corner reflectors will be discussed. The performance of reflectors cannot be properly examined without the knowledge of the feed configurations of the reflectors. For this reason , different types of feeding configurations will be illustrated in this thesis.
The corner reflector antenna of the V-shaped type constructed by two conducting planar surfaces has been extensively used since it was proposed by Kraus[l] . Since then, extensive theoretical and experimental analysis for this antenna have been carried out. The three dimensional corner reflector antenna consisting of three planar reflectors driven by a DA monopole has been reported to increase the gain by 5 dB with an input impedance of 50-75Q.
Recently a cylindrical corner reflector antenna was proposed. It is constructed by adding a cylindrical subsurface with a suitable radius to the V-shaped type. The addition of this subsurface introduces improvement in the gain , reduction of the sidelobe level and less dependence on frequency as compared to the V-shaped reflector.
In this thesis we propose two new antennas. The first antenna is formed of a right angle double corner reflector with aJ2-dipole feeding element , the second antenna is formed of a right angle double corner reflector with a horizontal plate and a 3k/4 - monopole feed. This has a surface reflector half that of the previous antenna with addition of an earthed conducting plate. The EMF method and the method of images are used in the derivation of the antenna impedance. A computer program is designed and used for calculating input impedances , gains and field patterns with different values of feeding element length L and radius a and over a range of distances between the feeding element and it’s images. Numerical results are discussed and reported in the two cases of the double comer reflector antennas.