Design Of Array Antenna For Roadside Unit In ETC System

With the rapid development of economy, both the developed and developing countries are facing the increasingly complicated traffic problems. Blindly strengthening the road network constructions cannot fundamentally solve those problems and will cause enormous resources waste. In order to achieve the most optimal use of transport infrastructure, the Intelligent Transportation System(ITS) has been extensively studied. As one of the most sophisticated systems in ITS, the Electronic Toll Collection(ETC) has been widely used in many countries. And as the key technology in Intelligent Transportation Systems, Dedicated Short Range Communication(DSRC) is also used in Electronic Toll Collection. Although China has been initially implemented the nationwide network of ETC system, the system is still faced with the adjacent lane interference and car-following interference issues that hinder the full development.The study on the array antenna for Roadside Unit of the ETC system is presented in this master’s thesis, and the contents are summarized as follows.Firstly, a brief introduction to the composition of Intelligent Transportation System and its key technologies are presented at the beginning. The construction, development status and the adjacent lane and car-following interferences of the ETC system are also introduced and investigated. To solve the interferences, the Roadside Unit of ETC system should have the ability to positioning the location of the car equipped with On-board Unit, which requires the Road Side Unit having a high positioning accuracy circularly polarized array antenna.Secondly, based on the investigation of ETC system and the circularly polarized microstrip antenna design method, the element antennas of the direction finding antenna in the ETC system are simulated. The microstrip patch antennas with different truncated corners and substrates are simulated.Then, the 1×8 and 1×6 multi-port array antennas are simulated. Furthermore, in order to improve the accuracy of the localization, it is necessary to reduce the mutual coupling of the array antenna. Therefore, based on the technologies of improving array antenna port isolation, 1×8 and 1×6 multi-port array antennas with EBG structures are both simulated and measured.Finally, the simulations of 1×8 and 1×6 single-port array antennas and their power dividers are finished.