In Multi-beam Focusing Lens Antenna

Aiming at the deficiency of validity of catching targets in single beam spot-focusing lens antenna, applying to ballistic wake microwave interferometer, a multi-beam spot-focusing lens antenna is mainly considered to design in this paper to augment the range of catching and enhance probability of hitting the target. Because single beam spot-focusing antenna is the basis and crux of multi-beam spot-focusing antenna, only beam deviation and corresponding influence in single beam are adequately and accurately analyzed, can multi-beam spot-focusing antennas be designed. We adopted Gaussian beam, ray tracing and vector diffraction integration together to analyze single beam spot-focusing lens antenna. The positions of the max values and half-power band widths in the focal plane of lens are also educed by means of the software matlab, which are more close to experimental values than ordinary geometry optics. Therefore we can deduce that the method in this thesis is successful. In addition, the experiments of the max-value positions of receiving power have been fulfilled in our laboratory when the transmit horn derivates from optical axes of lens. Results are fairly in agreement with those of the theory. A linear multi-beam spot-focusing lens antenna is given in the thesis. At last, the questions about beam forming network and coupling in multi-beam antennas are described. The outcome of the text provides a firm theory foundation for formal scheme of multi-beam spot-focusing lens antenna subsequently, which can be applied to plasma diagnose and focal plane array imaging. The measurement of electron density of ballistic wake is of great sense to national defense construct. And focal plane array imaging can be used to detect concealed weapons and explosives, develop autonomous aircraft landing system. Consequently they impel the progress in military affairs and aviation career, having an important society value.