Circularly Polarized Microstrip Array Antenna Technology

There are two ways that information transfers:cable transmission and wireless transmission. With the development of technology, wireless communication will play an increasingly important role in people's daily life. Since the characteristics of antenna have direct influence on the performance of the whole wireless application system, it is the key component of wireless systems. This thesis focuses on two aspects of wide-angle circularly polarized microstrip antenna array and low sidelobe circularly polarization microstrip antenna array.The main contents of this thesis are arranged as follows:1. Design an antenna array element working at 3 GHz based on wide-angle circularly polarized antenna. Then, design a four element linear array which has wide-angle scanning characteristics.2. Design a high performance circularly polarized microstrip patch unit working at 5.835GHz based on broadband circularly polarized antenna.3. In order to meet the requirements of Electronic Toll Collection System (ETC) working at 5.835 GHz, such as narrow-beam, high gain, miniaturization and planar figuration, we focus on the design principles of microstrip antenna array and propose an antenna array composed of 12 units. The array has a peak gain of 14dBi at operation frequency and side-lobe levels in the horizontal direction and vertical direction are-22dB and -21dB, respectively. Overall, antenna array meets the technical requirements of ETC.