Design And Implementation Of Extreme Low Side Lobe Reflector Antenna

Microwave transmission system has the advantages of low cost and easy construction.Hence,even in the 3G/4G era,as an effective supplement for optical network,it is always a high-volume requirement from the marketing.With the growing demand of high capacity transmission,the link sites are increasing.More and more microwave antennas will be installed on the same tower or roof,leading to easy interfere between antennas.In order to reduce the interference and influence from each other,more strict requirements for the antenna are proposed.In particular,antennas with lower sidelobe radiation pattern meeting different level RPE(Radiation Pattern Envelope)requirements,such as ETSI(European Telecommunications Standards Institute)Class 3,even ETSI Class 4,are highly demanded,which have a broad market application prospect.Therefore,the researches on those supper and extreme low sidelobe microwave antennas are very necessary.Taking the designs working at 23 G band as examples,this thesis introduces a Cassegrain antenna design meeting ETSI Class3 standards.Then,presents the design of a splash plate feed antenna,which achieves ETSI Class4 standards.These two designs follow industrial requirements.The main contents of this thesis are as follows:(1)The development status of microwave transmission antenna at home and abroad is given.Then,the research background,research significance,research purpose and research methods used in this thesis are briefly introduced.(2)The fundamental of reflector antenna is given.As the example,the basic electrical properties and the working principle of parabolic reflector are given.(3)The working principle and geometric structure of the dual reflector antenna are given,with the standard Cassegrain antenna as the representative.In particular,the influence of aperture on phase and amplitude,feed type and other basic contents are discussed.(4)To meet ETSI Class3 standard,a feed and the corresponding super low sidelobe Cassegrain reflector antenna are analyzed,designed and measured.(5)To meet ETSI Class4 standard,a splash plate feed and the corresponding extremely low sidelobe reflector antenna are analyzed,designed and measured.