Design Of Passive Dual-polarization Radar Reflector Tag

In the field of Traffic Information Collection,roads become more and more congested becauseof the increasing of motor vehicles.The unprecedented pressure on the Traffic InformationCollection System can not be effectively mitigated simply by building more transportationinfrastructure.Many methods have been used in the Traffic Information Collection System,such asVideo Surveillance,Microwave Detection,GPS Positioning and Induction Coil Detection.Thesetechniques all have their own defects or inadequacies in the aspects of all-weather, all-round,timeliness or accuracy. The core procedure of Traffic Information Collection is the detection andidentification of vehicles.So trying to enhance the accuracy of detection and identification caneffectively enhance the credibility of the collected traffic information.After in-depth analysis,this paper proposed an effective solution which use the radar reflectorinstalled on the vehicle combines with the traffic detection radar system.There are two types ofradar reflector now being used,corner reflector and spherical dielectric lens.Neither of them issuitable for the proposed system due to the complex structure and big size.The radar reflectorwhich the program required must have the following characteristics,easy to identify and smallsize,also the production cost should be low.The solution which combine use the radar reflector with the traffic detection radar system ispresented after the introduction of the current traffic information collection technologies and theadvantages and disadvantages analysis.Then a detailed analysis of its effectiveness andenforceability is given.After the introduction of the definition of radar cross section and thederivation of the radar equation,the key factors which affect the performance of the radar targetrecognition are discussed,such as the scattering characteristics of target and the polarizationmatching between transmitting antenna and receiving antenna.In order to elaborate the concept ofpolarization match,the polarization property of electromagnetic wave is described in detail,then theconcept of cross-polarization is introduced.The co-polarized response requires the transmitting andreceiving antenna have the identical polarization,while the cross-polarized response requires thepolarization of transmitting and receiving is mutually orthogonal.At high microwavefrequencies,the co-polarized response of most objects is far stronger than its cross-polarizedresponse.Accordingly,this polarimetric characteristic of the complex background can be utilized todesign a radar reflector that with bigger RCS in cross-polarization configuration to enhance theratio between the signal and the background echo. This paper proposed a novel design of radar reflector which use the L-shaped metal resonatoras the basic element in the array to improve the cross-polarized response.The three-dimensionalelectromagnetic simulation platform FEKO was used for modeling and simulation.The optimizeddesign scheme was manufactured and measured.Then,in order to reduce the overall size of thearray,methods of decoupling have been studied and summarized,the direction of future researchabout this subject is pointed out.At last,a new type of radar tag which use the L-shaped slot insteadof the L-shaped metal resonator as the basic unit in the array was proposed.The results of this papershowed that both types of radar tag can highly improve the ability of the radar detection to theinstalled objects.On the basis,a new way to the collection of traffic information was provided,andnew type of Intelligent Traffic System could be developed.