Research On Retrodirective Antenna Array Based On Butler Matrix

With the development of modern science and technology,the use of antennas is more and more complex.Due to the performance of the antenna in various aspects of the demand,so a variety of new antenna technology is proposed.The retrodirective antenna of smart antenna is one of the research hotspots.It can make the returned signal automatically point to the direction of the incoming wave without knowing the direction of the incoming wave.Retrodirective antenna is generally realized by phase conjugate principle,and is widely used in information communication and radar applications due to its advantages of high-speed tracking capability and high cost performance.Despite the advantages of retrodirective antenna,most of the current retrodirective arrays are realized based on Angle reflector,Van Atta array,mixing circuit,phase-locked loop,digital circuit.And in this thesis,based on Butler matrix design and manufacture a kind of retrodirective antenna system,and can take advantage of the control circuit to control the effect of back.The main contents of this thesis are as follows:(1)The existing retrodirective arrays are listed and the advantages of each retrodirective array are analyzed theoretically.Then,the current research status and implementation form of Butler matrix are analyzed.Then,the design principle of Butler matrix is briefly described,and a retrodirective array based on Rotman lens is introduced,which provides reference for designing retrodirective array using Butler matrix.(2)A Butler matrix for X-band was designed: its schematic model was built in advanced Design System software to preliminarily verify its performance,and its structure was further optimized in HFSS.During the design,the principle of directional coupler,cross junction and phase shifter are analyzed and their structure is designed and optimized.Finally,the overall structure of the design,through the full wave electromagnetic simulation software,the final size of the structure.In this thesis,Butler matrix without cross junction and Butler matrix without cross junction are designed.Both Butler matrix structures can meet the design requirements in 9.8ghz ? 10.2ghz working bandwidth.Finally,the possibility of using Butler matrix to realize retrodirective array is analyzed from the phase change of signal.(3)Two kinds of microstrip antenna arrays are designed.When the internal structure of the antenna is improved,a complete retrodirective antenna system is constructed by combining Butler matrix.Full-wave electromagnetic simulation is carried out to verify the performance of the system when it is used as a multi-beam antenna,and then the directional backtracking performance of the system is tested when plane waves are incident from different directions.The Radar Cross Section(RCS)of antenna arrays under different conditions are compared.Because RCS can represent the scattering status of the system,the directional backtracking performance can be verified by comparing the RCS value of the antenna array in the incident direction before and after using the feed network.Finally,a control circuit is added to the designed directional backtracking array to adjust its RCS value according to the demand.