Uniform Multibeam Regional Lens Antenna

Millimeter wave imaging technology is getting more and more attention in the field of millimeter wave in recent years. The passive millimeter wave imaging technology obtains images by detecting radiation energy. It has no sources and could avoid active target scintillation. Focal Plane Imaging is one of the most significant systems in millimeter wave imaging technology, as a result of the facts ,this technology has many advantages, such as real-time imaging, particularly for fast-moving targets, simple structure and easy implementation, it has been widely utilized in anti-terrorism security, scenes of surveillance, military reconnaissance and other fields.Focal Plane Imaging System produces a number of different pointing beams and covers a wide-range by many receiving units arraying on the focal plane. In this thesis, multi-beam focal plane dielectric lens antenna has been designed, it has many advantages such as feeding block, designing flexibility, structure compact, and easy processing. The implementation can produce uniform multi-beam in a wide field of view in a wide frequency band.In this thesis, various performances of electrically large multi-beam lens antenna have been investigated making use of equivalent feed and GO (Geometrical Optical) of FEKO and overcoming difficulties in solving large objects. Study aspects include the following:1) Research on the arrangement of feed horn and its impact on the antenna radiation characteristics in 3mm-band. A hexagonal array feed arranging triangles in the focal plane has been designed. Compensate effectively for the phase deviation caused by off-focus feeds. Implement 3dB crossover between adjacent beams.2) It's very important to choose a reasonable lens surface. A double convex dielectric lens antenna has been designed. It can achieve a uniform multi-beam field in wide-angle scanning by comparing radiation characteristics of a variety of lens. 3) Zoned lens antenna has been designed using the Fennel Principle. It not only can reduce the weight of lens with no affection to the performance of lens, but also can take a great convenience for actual processing, testing and using.4) A 500mm diameter lens antenna has been designed. The feeds array of the antenna employs staggered distribution, and it can achieve a more accurate sampling by dynamic scanning a large range.5) Studied mutual coupling between multi-beams to prepare for the experiments.