Radiation characteristics of corner reflector antennas.
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This thesis presents a study of the radiation characteristics of corner reflector antennas. The influence of the design parameters on the radiation characteristics are assessed using an analytical method and the Finite Difference Time Domain (FDTD) method. The FDTD method for corner reflector antennas which are electrically small to medium sized antennas is developed in detail. The important subject of the Absorbing Boundary Conditions (ABCs) is studied including a study of Mur ABC and Perfectly Matched Layers. It is shown that both methods reduce the reflections from the boundaries sufficient so that the far-field radiation pattern can be computed accurately. An analytical solution to compute the far-field radiation pattern for infinite comer reflector antennas is derived and used to understand the radiation mechanisms. Based on those results, the FDTD method is used to conduct a parametric study on finite sized comer reflector antennas. Experimental antennas have been built and measured in order to verify the computational predictions. Very good agreement is reported The novel idea of a variable beam-width comer reflector antenna is developed and practical designs of such an antenna are presented. The principle is to design the comer reflector antenna such that the beam-width of the antenna can be precisely modified. Data on the gain and beam-width are presented. This has been done both by computational and by an experimental model. The influence on the performance of the comer reflector antenna when substituting the solid reflector plates by rods has been investigated. The computational predictions have been verified by measurements of an experimental antenna. Very good agreement has been achieved. III[ The possibility of modifying the shape of the comer reflector antenna is investigated. It is shown that a modified comer reflector antenna with less depth produces the same far-field pattern as a standard corner reflector antenna. It is also shown that the performance of small aperture size corner reflector antennas is superior to a cylindrical parabolic reflector antenna.
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