Research On Broadband Dual Polarization Antenna And Its Array Technology

With the increasing demand for high-speed transmission of information such as images and videos,mobile communication technology has developed rapidly,and the bandwidth of communication systems has been further expanded,which has placed more and more challenges on the design of antennas for mobile communication systems.Dual-polarized antennas are widely used in modern mobile communication base station systems because they can improve the multipath fading problem of the system and improve the communication capacity of the system.In this paper,based on the current research status of dual-polarized antennas,a wide-band magnetoelectric coupling feed patch antenna,a hybridfed dual-polarized antenna and its array are designed.In order to validate the designs,the prototypes of the proposed antennas are fabricated and tested.Measured results show that the proposed antennas have wide differential impedance bandwidth and stable radiation patterns.The main innovative research contents of this work are summarized as follows: 1.Research on broadband technology of microstrip patch antenna.In view of the trend of wideband and low-profile development of antennas in current mobile communication systems,the author designed a wideband patch antenna.This antenna is composed of a square radiating patch with four chamfers,two feeding open loops,a modified T-junction power divider,and a ground plane.By slot coupling,ring current is produced on the metal open loops,exciting the radiating patch to produce directional radiation.To simplify the feed structure,the two loops are placed mirror symmetrically,and the two output microstrip lines of an equal T-junction power divider are rotated deployed to excite the loops.This design avoids a 180° delay line for a traditional power divider,which has frequency dispersion effect.In addition,a pair of open-ended microstrip transmission lines are added to the Tjunction power divider,which increases a new resonance for the antenna,realizing the thirdorder matching and extending the impedance bandwidth of the antenna from the original 1.72-2.7 GHz to 1.68-2.83 GHz.A prototype of the proposed antenna was fabricated and measured.the measurement and simulation results show that the proposed antenna achieves wide bandwidth with low profile.2.Research on hybrid feed broadband dual-polarized antenna and array.Based on the current research hotspots of modern mobile communication,we design a broadband dual-polarized antenna with hybrid feed structures.This antenna consists of a square radiating patch,two orthogonally placed feed structures and a metal reflector.Two different feeding mechanisms are designed to excite two orthogonal modes on a single radiating patch.One of the modes is excited by a magnetic-coupled feeding structure,while the other is excited by an electric-coupled feeding structure.The magnetic-coupled feeding structure consists of a metallic loop with a gap and an open-ended transmission line.The electric-coupled feeding structure is comprised of a series capacitor and an impedance transformer which realizes 180° phase shifting.Measured results show that the proposed antenna has 52.3%(1.63-2.78 GHz)and 47.3%(1.68-2.72 GHz)impedance bandwidth with return loss > 10 dB for port 1 and port 2,respectively.Owing to the hybrid feed structure,the isolation between two ports is better than 26.5 dB.The proposed antenna is suitable for modern wireless communication systems.Moreover,a 1×8 broadband horizontally/vertically(H/V)polarized linear array is proposed based on the dual-polarized antenna element.Simulation results with the HFSS software show that the array has good performance.