A Research Of Ultra-wideband Phased Array Antenna Based On Connected Array Technology

Phased array antenna has the advantages of accurate beam pointing,fast scanning speed,multi-target recognition and tracking,and plays an important role in communication systems in many fields.In order to meet the integration and multi-function requirements of modern systems,ultra-wideband(UWB)phased array antenna technology is paid more and more attention.The main content of this article is as follows:Firstly,the principles,characteristics and development status of long slot array antenna,tapered slot antenna,connected array antenna and tightly coupled array antenna are investigated and studied.At the same time,the principle of Wheeler current sheet involved in infinite array is described,and the impedance characteristics and scanning characteristics of connected array are analyzed based on Green’s function of infinite array.Secondly,two kinds of UWB array antennas based on the principle of Tapered Slot Antenna(TSA)are designed by using the periodic boundary characteristics,and the technology of reducing cross polarization is expounded.The first antenna adopts the traditional Vivaldi structure,which realizes the ultra-wideband operation performance from 0.35 GHz to 4.5GHz,but this structure has poor cross polarization performance.In order to overcome the disadvantage of poor cross polarization performance,the second antenna improves the cross polarization characteristics by cutting the large current loop on the radiating fin.Good impedance matching and cross polarization performance are achieved at 0.35GHz-4.5GHz by adopting a novel slice notch structure.Finally,based on the connected array technology,an ultra-wideband connected array loaded with resistive card is designed by using the coupling between units.The array unit adopts a new type of symmetrical oscillator,which includes parasitic patch,loading capacitor,resistive card and UWB balun.At 0.4GHz-4.5GHz,the active VSWR is less than 2.6 when the scanning angle of the array is 60 degree,and the average efficiency of the array reaches 70%.