The Research On C-band Multi-beam Planar Lens Antenna

Compared with the reflective surface antenna,the lens antenna has advantages such as no feed source blocking,small gain reduction when the feed source is defocused,and easier beam scanning.The Luneburg lens antenna has good symmetry,but its processing is difficult and its volume is relatively large,which does not meet the development direction of miniaturization and integration of the antenna.Planar lens antennas have the advantages of small size,simple manufacturing process,low cost,easy integration,and the like,and are widely favored by antenna designers.This article focuses on the research and design of multi-beam planar lens antennas based on frequency-selective surfaces.The use of periodically-aligned patches and dielectric-plate combined units replaces traditional lenses equivalently to increase the gain of the antenna and place multiple feeds to realize the multi-beam function of a planar lens antenna.This paper first introduces the background of the lens antenna and the development status of the multi-beam lens antenna at home and abroad,and analyzes the development status at home and abroad.Then it introduces the lens antenna classification,working principle and analysis method,and focused on the theory of planar lens antenna.Then,the feed of the planar lens antenna is designed,the horn antenna is selected as the feed of the planar lens antenna,and a waveguide horn antenna working at 6 GHz is designed.At the same time,the structure of the planar lens is designed.The square patch,regular hexagonal patch and circular patch planar lens structure are designed.The planar lens structure is similar to the frequency selective surface.The core of design planar lens structure is the planar lens periodic unit.The periodic unit uses a three-layer structure,including double metal patches and single-layer dielectric plate.The dielectric plate of FR-4 has a dielectric constant of 4.3.The dimensions of the final designed square patch,regular hexagonal patch and round patch planar lens are 216mm×216mm×1.6mm,204.1mm×204.1mm×1.6mm,and 211.5mm×211.5mm×1.6mm.The focal length ofthe planar lens is determined to be 440 mm,379mm and 380 mm,respectively.Finally,the characteristics of designed planar lens antenna are simulated.The waveguide horn antenna is used as the feed source.The maximum gain is 6.47 d Bi.The gain of the antenna after loading the planar lens was improved by 7.0d B,7.53 d B and 7.93 d B,respectively.The pattern characteristics of the three-type patch antennas was compared.A round patch planar lens antenna was selected to study the multi-beam performance.In the study of multi-beam functions,two methods are used to implement.The first method rotates the feed along the Y-axis by 5°,10°,15°,20°,25°,and 30° to simulate the beam characteristics of the designed planar lens antenna.According to the simulation results,the beam energy can generate a 30° deflection with a maximum gain reduction of 0.65 d B,and the beam scanning function can be achieved within the range of 30??.The second way is to load multiple feeds at the same time for simulation.Select three feeds arranged at a distance of-67 mm,0,and 67 mm to generate three beams with a beam deflection angle of 48??.