Research And Design Of Marine Microstrip Patch Antenna

For ships far from land,positioning and navigation functions are indispensable,and there is a need for communication within the ship and the ship with exterior.Of Marine positioning system,communication system with the outside world,WLAN,Bluetooth and other equipment used for communication inside the ship,antenna is the core component,so its analysis and optimization value is far greater than other components.The microstrip patch antenna,which combines the circular polarization technology and dual-frequency technology,is suitable for the special working environment of ships,and at the same time,it can better meet the requirements of the composite antenna with simple structure,excellent performance and multi-frequency work.The existing designs of single-frequency and dual-frequency circular-polarized microstrip antennas still have great room for improvement in antenna structure,operating bandwidth and gain.In view of the ship’s demand for antenna with simpler structure and better performance parameters,this paper mainly does the following work:(1)The basic parameters and radiation mechanism of the microstrip antenna are described and analyzed,and two commonly used feeding technologies,three circular polarization technologies and three dual-frequency technologies are analyzed.(2)The single-frequency circular-polarized microstrip antenna with two common structures and a new structure is designed.The simulation results show that the operating frequency bands of the three antennas all cover the frequency bands of 2483.5～ 2500.0MHz of Beidou RDSS positioning system and Globalstar satellite communication system,and all the parameters meet the requirements of engineering design.Compared with the 3d B axial ratio bandwidth of 40MHz(1.6%)and 160MHz(6.4%)of the two common antennas,the antenna of the new structure reaches 305MHz(12.2%).Moreover,the antenna size of the new structure is relatively small,and the gain,standing-wave ratio and-10 d B impedance bandwidth are approximate.(3)A new dual-frequency circular polarized microstrip antenna structure is designed.Based on the new single-frequency circularly polarized antenna designed above,the dual-frequency circularly polarized antenna is realized by loading a proportionally reduced type slot in the center.Simulation results show that the parameters such as standing wave ratio,return loss,axial ratio and gain of the antenna in 2.5GHz and 3.5GHz bands all meet the requirements of engineering design.The low frequency of the antenna is applicable to the Beidou RDSS positioning system or wireless communication systems such as WLAN and Bluetooth,as well as Globalstar systems.The high frequency can be used for 5G communication within inland ships and base stations after docking.Compared with a variety of existing dual-band circular polarization microstrip patch antenna,the gain and relative bandwidth of the new antenna structure are better than that of the antenna structure with the same complexity;Compared with the same gain and relative bandwidth of the antenna structure,the overall complexity is greatly simplified.(4)In view of the problem that the performance of a single antenna unit often cannot meet the engineering requirements,the related theories of microstrip antenna array are briefly analyzed.Several factors affecting the antenna array performance are discussed,and the influence of cell spacing on the antenna array performance is studied and analyzed in detail by using simulation software modeling.A simple four element linear antenna array and a plane antenna array are composed of the dual-frequency circularly polarized antenna above as the element,and the analysis is given here.