Research On Multi-function Integrated Antenna In Intelligent Transportation System

Intelligent transportation system (ITS) involves a variety of antennas, such as AM/FM broadcasts,wireless local area network, satellite digital audio radio service, global positioning system, globalsystem for mobile communications, remote keyless entry and automotive radar. Various antennas areused independently in the car, which may cause complicated electromagnetic environment, take uplarge space and affect the aesthetics function. Microstrip antenna has been widely used in varioustypes of radio equipment for its small size, low profile and easy integration, which meet theminiaturization and integration trends. Based on the method of multi-substrate stacked and gap loaded,dual and tri-band vehicle antenna units for ITS application are designed in this paper, and thetechnology of current meandering and dielectric loading are researched.The main research in this paper can be summarized as follows:1. The technology of multi-band for microstrip antenna is investigated, the advantages anddisadvantages of multi-substrate stacked and gap loaded are analyzed, and the issue for highfrequency ratio is discussed. Based on the method of multi-substrate stacked, with shifting the upperradiating patch, a single-fed circularly polarized patch antenna for GPS and DSRC is designed. Basedon the technology of gap loaded, a single layer circularly polarized antenna for GPS and DSRC isdesigned with two feeding points. The miniaturization of antenna is studied by slotting on theradiation patch or the ground plane, and the effect of the slots on the electrical performance of theantenna is discussed.2. Based on the dual-band antenna, a tri-band patch antenna for GPS, WLAN and DSRC isdesigned with single feeding point, which combines multi-substrate stacked and gap loaded.Compared with three layers stacked for tri-band, the structure of this design is much simpler and doesnot require additional matching network. The experimental results show that the design is correct.3. For the problem of low gain in the designed antenna, we study the methods of dielectricloading and analyze the influence on impedance characteristics, patterns and peak gain. Thesimulation results show that the tri-band patch antenna can improve its gain by loading substrate witha low dielectric constant and a superstrate layer with high dielectric constant respectively.