Research On Planar Lens Multi-beam Antenna Technolog

Multi-beam antenna technology is widely used in the fields of navigation,communication and detection because it can significantly increase the number of beams,expand the scanning area,increase channel capacity and maximize the utilization of frequency resources.With the advantages of simple beam control method,easy design and low cost,Rotman lens stands out among many multi-beam antennas and attracts more and more attention and applications.At the same time,because it is essentially an ultra-broadband feed network,it is often used as a broadband power divider,multiplexer,and frequency divider in the microwave field.Nowadays,there is a large amount of research literature on Rotman lenses,but most of them are focused on the study of Rotman lenses in the higher frequency bands,while there are only a few studies on the problem of large size of Rotman lenses in the lower frequency bands.In this paper,the design of planar Rotman lens antenna with center frequency of 3.6 GHz is developed,and the main research contents are as follows:1.Based on the design technique of Rotman lens,the parametric simulation discussion,contour drawing,and modeling simulation of Rotman lens,a 5-input 8-output planar microstrip Rotman lens is designed,and the amplitude and phase simulation analysis of the array port of this lens is performed.An antipodal Vivaldi antenna is designed,and its multi-beam pattern is simulated and analyzed jointly with the Rotman lens,with beam pointing angles of ±28°,±14°,0°,respectively,and an antenna array gain of greater than 1.8 d Bi in this range.2.A blind-hole slow-wave structure is designed,its influencing factors are simulated and analyzed,and loaded into a microstrip patch antenna and a tapered transmission line respectively.Based on this,two equivalent electromagnetic parameter extraction methods are proposed,and the measured and simulated results show that for the same slow-wave structure,the extraction of equivalent dielectric constant is independent of extraction method.3.For the designed blind-hole slow-wave structure,firstly,it is applied to the design of microwave T-type power divider to achieve 84% reduction in circuit size and 2 d B improvement in isolation;secondly,it is applied to the design of planar microstrip patch antenna to achieve68% reduction in size;finally,it is applied to the design of planar Rotman lens antenna to achieve 41% reduction in lens size.in addition,the simulation compares the performance of Rotman lens under two different slow wave loading methods.One is that the slow wave is loaded in the lens cavity only,and the other is that the slow wave is loaded in the lens cavity and the antenna array at the same time.The results show that the maximum gain of the original antenna array can be increased by 1 d Bi and 1.9 d Bi for the two loading methods without any significant change in the side-lobe level and the input reflection coefficient of the antenna array,which means the efficiency of the antenna array is improved.4.The T-type power divider and planar microstrip patch antenna after slow wave loading,planar Rotman lens,and planar Rotman lens antenna are physically processed and tested,and the measured results are in good agreement with the simulation results,indicating that the theoretical analysis,model design and electromagnetic simulation of the thesis are correct.