Research On Beam Scanning Array

Antennas with beam electrical scanning capability have shown to be superior to mechanical scanning.For example,their beam can flexibly scanning without inertia,which make them been widely used where fast beam electrical scanning capability is required such as for the applications in radar,wireless communications,or electronic countermeasures.As typical beam scanning antennas,the phased arrays,frequency-scanning antennas,and beamscanning antennas based on lens and matrix feed have attracted a lot of attentions from designers.The phased arrays,frequency-scanning antennas own continuous beam scanning capability,while antennas based on lens and matrix feed can only provide discrete beam scanning capability but with low-cost.For the high-performance platform represented by the aircraft,the antenna should be designed to conformal with its platform,hence,the layout of units,phase-shift,and beam control of the beam scanning antenna are extremely different from the traditional planar ones.Based on this background,the design of beam scanning techniques and conformal phased array antennas are studied in this thesis,and the works have been finished are shown as following:Firstly,a systematic investigation on different varieties of beam scanning technology is presented,aiming at provides the advantages and special characteristics of them.Base on which,some beam scanning principles will be chosen as the candidates for later designing of beam scanning array characterized by conformal and low-cos.Secondly,a CAD(Computer Assistance Design)software toolkit for phased array design is developed,which provides a general and powerful tool for the design of phased array especially for large scale arrays.Thirdly,a low-cost beam scanning antenna based on Rotman lenses is designed.The basic theories,design process and model of a Rotman lenses are presented,the simulation results verify its beam scanning capabilities.Finally,the design of a hemispherical conformal circular polarization phased array antenna is presented.The broadband design of antenna elements,optimization of the conformal arrangement of the array,beam scanning algorithm,and low sidelobe design technologies are studied in detail.The simulation and testing results of the prototype show that the performance of the array antenna satisfies the requirements,which is highlighted by the high gain and low sidelobe when the beam scanning within the desired half space.The experience and results shown in the thesis can be directly used in the design of conformal phased array or other beam scanning antennas,which make it has certain reference value and application potential.