Design Of Low-cost Beamforming Network For Phased Array

Phased array antennas have become an important technology in the military and com-mercial fields with their unique advantages.With the continuous development of phased array technology,the continuous improvement of performance and frequency band re-quirements leads to higher and higher production costs,which is difficult to promote to the civilian field.Therefore,finding effective solutions to reduce the cost of phased array antennas deserves our in-depth study.The purpose of this thesis is to find a solution to re-duce the complexity of the phased array to realize the low cost of the phased array system,and to study and discuss the related design ideas and principles involved in the solution.The main work of this thesis is to introduce a low-cost feed network based on Coher-ent Radiating Periodic Structure(CORPS),Coherent Beamforming Network(C-BFN).The characteristic of this feed network is that it can realize power distribution and beam control of N+K array elements through N input K-layer C-BFN.Compared with the tradi-tional phased array antenna,each array element needs to be Independent T/R component control,the advantage of using this feed network is that the number of T/R components used can be reduced,thereby reducing the complexity of the phased array antenna,that is,reducing the manufacturing cost of the phased array antenna.Considering the synthesis efficiency of the feed network and the scanning capability of the system,the feasibility analysis of the feed network at different levels is carried out.In this thesis,a single-layer feed network structure with two inputs and three outputs is finally adopted.In addition,the design of a two-dimensional feed network can be realized by cascading the single-layer feed network.Realize power distribution and beam steering for 3×3 array elements.This scheme can reduce the number of traditionally required T/R components from nine to four,realizing the low-cost design of phased array antennas.At the same time,the advantages and disadvantages of the feeding network are also analyzed,and a one-bit digital phase shifter is designed for the problem of narrow beam scanning angle.By improving the design of the traditional switching linear phase shifter,the phase shifter reduces the size of the design and the number of RF switches used in the physical structure,and reduces the insertion loss of the phase shifter.Finally,a microstrip Yagi antenna is designed as the radiating element of the feed network,which is integrated with a digital phase shifter and then connected with the designed feed network to form a complete antenna system.The actual test results are compared,and the relevant parameters and beam steering char-acteristics of the feed network are verified.