Research On Navigation Circular Polzrized Microstrip Antennas And Arrays

With the rapid development of satellite navigation and positioning systems,Global Positionning System(GPS)has become more and more widely used in military and civilian fields due to its advantages of high positioning accuracy,wide coverage,fast response speed,and ability to work around the clock.Bei Dou Navigation Satellite System independently developed by our country has developed rapidly.On the basis of including the GPS function,it also has the function of short messages and two-way exchange of information.As the application level of satellite navigation and positioning systems tends to be diversified and complicated,the antenna as a terminal of the satellite navigation system is bound to develop in the direction of stronger compatibility,lower profile,smaller size,and lighter weight.The circularly polarized microstrip antenna as a classic antenna form has a low-profile,miniaturized theoretical basis and a large number of practical engineering applications.This article will use this as a starting point to study and analyze the design method of the Beidou circularly polarized microstrip patch antenna.In the fields of radar communication systems and satellite navigation systems,circularly polarized antennas have been widely used because of their simple structure,low cost,reduced multipath effect,and the ability to receive arbitrary polarization transmission signals.Compared with the unit antenna,the array antenna has the advantages of high gain and strong anti-interference ability,so it is more suitable for long-distance communication of the satellite navigation system.In this paper,through the analysis of the characteristics of circularly polarized microstrip antennas,the miniaturized design of antennas and the mutual coupling of antenna arrays,a small circularly polarized microstrip array antenna designed for satellite navigation systems is designed.The main research contents are as follows:Firstly,the background and significance of the research on the topic of navigation circularly polarized microstrip antennas and their arrays are described.The advantages and disadvantages of the four main satellite navigation systems in the world are compared,and the research progress and the Beidou navigation system in China are introduced in detail.Major breakthrough.The research status of circularly polarized antennas at home and abroad is introduced and the characteristics,relevant basic theoretical knowledge and design methods of circularly polarized antennas are summarized,including: 1)The use of high dielectric constant dielectric plates to achieve the miniaturized design of microstrip antennas;2)Expand the bandwidth through the defective ground structure;3)Adopt the double-feed point feeding form combined with the power split phase shifter to achieve the phase shift of the 90 ° output port,so as to achieve the effect of circular polarization.Secondly,according to the constraints of practical application,two antenna unit forms of single-feed circularly polarized microstrip antenna and doubly-feed circularly polarized microstrip antenna are designed.The high dielectric constant dielectric plate is used to reduce the antenna size.The bandwidth of the single-feed circularly polarized microstrip antenna is increased by 28% by increasing the defect ground structure.With the good matching characteristics of the feed network,the effect of widening the bandwidth can also be achieved in the double-fed circularly polarized microstrip antenna.Thirdly,in order to solve the problem of mutual coupling of small-pitch array antenna elements,a method of filtering ground current coupling by using a ground structure slot is proposed when the single-feed circularly polarized microstrip antenna array is formed,by adjusting the number and width of the ground slot structure To achieve the effect of decoupling.Compared with the untreated array,etching the trench structure on the floor improves the isolation between array elements,and the axial bandwidth increases by 9 MHz.In the doubly-feed circularly polarized microstrip antenna array,it is proposed that each antenna unit uses a separate dielectric plate and floor,and at the same time reduces the coupling strength between the array elements through the choke groove.In the design of the BD2 B3 compatible GPS L1 anti-jamming antenna array,it has a high degree of isolation and the axial ratio bandwidth can reach 32 MHz.Finally,by analyzing and demonstrating various parameters of single-feed and double-feed circularly polarized microstrip array antennas,the double-feed circularly polarized microstrip array antenna was selected as the terminal antenna of the satellite navigation system.The far-field test of the completed circularly polarized microstrip array antenna was conducted in a microwave darkroom,and the test results were basically consistent with the simulation results.In the process of verifying the anti-interference performance of the antenna array,the LCMV criterion was used to simulate and verify the anti-interference performance of the satellite navigation microstrip array antenna.The simulation results show that the anti-interference performance of the antenna array is good.The compatible dual-band antenna array has stable system performance in a wide frequency band,and the miniaturized and lightweight design meets the expected requirements.It is suitable for satellite positioning equipment such as bomb and small unmanned aerial vehicle.