Research On Reconfigurable Beam Scanning Array Antenna

Wireless communication technology has been developing vigorously in recent years.As an important part of it,antennas have gradually developed with various functions and styles.Among them,the reconfigurable beam scanning antennas with high gain are widely used in radar systems,satellite communications and other fields.Compare to traditional high gain antenna like phased array and parabolic antenna,reconfigurable reflectarray antenna has the advantages of low manufacturing cost,simple design,and flexible beam scanning capability.It has broad potential application prospects in satellite communication,5G ground mobile communication system,and even the sixth generation mobile communication system.The literatures of reconfigurable reflectarray antenna at home and abroad are investigated in this thesis.After that,two type PIN diodes are measured and the equivalent circuit models are extracted.On this basis,the electrically controlled reconfigurable reflectarray antennas with different polarization and different bits are studied in the 3.5-GHz band used by 5G.The main research contents and innovations are as follows:First of all,a design method of 1-bit linearly polarizd reconfigurable reflectarray antenna is proposed.Phase-shifting is realized by loading a PIN diode in each element to reconstruct its resonant structure size.The effect of the element’s structure parameters on the phase-shifting is analyzed,and the elements’ distribution of the array is optimized using the reference phase.A DC control circuit is designed to measure the processed antenna,the measured results deviate slightly from the simulation results.But the processed antenna still achieves good two-dimensional beam scanning performance.Then,in order to satisfy the requirements of circularly polarized antenna,a 2-bit circularly polarized reconfigurable reflectarray antenna is designed.The element is composed of a 2-bit reflective phase shifter and a circularly polarized antenna feeded by power divider with phase-shifting line.A total of 3 PIN diodes are loaded.The number of diodes used is small and the design of the control circuit is simple.After simulation analysis,the antenna composed of 12×12 elements can achieve a two-dimensional beam scanning range of ± 60 °.The maximum aperture efficiency reaches 24.3%,which is significantly higher than the proposed 1-bit linearly polarized reconfigurable reflectarray.Finally,in order to further improve the aperture efficiency and reduce the phase quantization error,a 3-bit phase-controlled circularly polarized reconfigurable reflectarray is designed,which is realized using the principle of rotating element’s structure.Each element is loaded with 8 PIN diodes for state switching.The DC control circuit is designed and the array are measured,the array composed of 8×8 elements can achieve a two-dimensional beam scanning range of ± 60° and good dual-beam radiation performance.The maximum aperture efficiency of single-beam operation is 27%,which is slightly lower than the simulated aperture efficiency of 32.2%.The element in this design scheme has stable performance at wide-angle oblique incidences and low loss.The antenna has small phase quantization error and high aperture efficiency.The two design schemes of circularly polarized reconfigurable reflectarray in this thesis can provide good ideas for the follow-up research.