Array Antenna Technology By Radial Line Feed

With the rapid development of radar,satellite and radio frequency microwave systems,people have higher and higher requirements for antennas in detection and communication systems.The radial line array antenna with less loss,simple structure,small size,and low cost is called a hot spot of people's competing research.The author conducts research on the high gain and wide bandwidth technology of radial line array antennas,and lays the foundation for the design of radial line fed broadband high gain array antennas.The main contents are summarized as follows:(1)In order to design a broadband radial line power divider,a comparative study of the bandwidth characteristics of the electrical coupling,magnetic coupling and magnetoelectric coupling probes in the radial line is carried out.The simulation results show that the electrical coupling probe has the widest operating bandwidth.Afterwards,the radial line power divider of the electrically coupled probe type was optimized to improve the bandwidth and VSWR performance of the radial line power divider.(2)The helical antenna with short circuit loading is designed.The overall size of the antenna is 60 mm*60 mm*40 mm.In the 8GHz-12 GHz frequency range,the maximum gain is 11.3d Bic,VSWR<1.5,it has better gain and bandwidth than short helical antenna.Using this antenna as the antenna unit of the radial line array antenna,a two-turn 18-element radial line array antenna was designed to obtain a maximum gain of 18.5 d Bic,a 3 d B gain bandwidth of 37 %,and a 3 d B axial ratio bandwidth of 40 %.Verified its broadband performance.And based on the two-turn 18-element radial line array antenna,a ten-turn 330-element broadband high-gain radial line array antenna was designed,which achieved 49 %impedance bandwidth(VSWR<2),42 % axial bandwidth,radial line array antenna with a maximum gain of 33.12 d Bic,and an aperture efficiency of 81% at the center frequency.The designed circularly polarized radial line array antenna has an all-metal structure,has extremely low loss,and has a simple structure and is easy to process.(3)A four-element sub-array antenna using a magnetoelectric dipole as the antenna element and a rectangular radial line as the feed is designed.The maximum gain is 15.8 d Bi,and the3 d B axial ratio and impedance bandwidth both cover the X-band(8 GHz-12 GHz).And it has been processed and tested,and the test results are basically consistent with the simulation results,which verifies the correctness of the design.By adopting the T-junction power divider of the air strip-line structure to feed the sub-arrays,an array antenna with a parallel feed structure is formed.The whole structure is an all-metal structure except that the probe position is fixed by a dielectric sleeve,which reduces the loss of the array antenna as much as possible.The designed 256-element radial line array antenna has a size of 423 mm*432mm*25 mm,has a linear polarization gain greater than 32 d Bi in the entire X-band,has a symmetrical pattern,has 95% aperture efficiency and greater than 40% The impedance bandwidth.Compared with the circularly polarized radial line array antenna with circular arrangement,it has a significant improvement.Compared with the traditional array,its performance is better.