Study Of Miniaturization Of Microwave Circuits And Antenna For Mobile Communication

With development of modern wireless communication technology and combination of advanced MIC and SOC technology, wireless communication anytime and anywhere is becoming reality.For communication system, miniaturization and high-performance becomes a hot research focus, for which photonic band gap structure provides a new method. Compared with traditional design methods and technology, this article puts emphasis on application of EBG in MIC and research in miniaturization of mobile antenna. Through analysis, design and measurement of real products exhibit the characters of EBG and miniaturized mobile antenna are exhibited.Since E.Yablonovitch and S.John presented the period structure-photonic band gap (PBG), it was introduced to application in MIC, the term PBG changed to EBG in microwave applications and attract extensive attention. Lots of theory analysis and test had been proposed. Recently the research of EBG has been focused on passive apparatus, such as filters, harmonic control and antenna performance improvement, etc. Some novel, compact EBG structure has been proposed. Besides, thinking to the packaging problems, Nesic presented technology without etching on the ground. Based on EBG structure, Korea scholars presented DGS structure. EGB has become a new method of miniaturizing and improving performance of communication system.In wireless communication system, the character of antenna will directly affect the system's communication quality. The rapid development of wireless communication technology puts higher request to terminal antenna. In recent years, miniaturization and multiband technology of antenna have aroused more attention. Mobile communication has experienced 1G(analog system), 2G(GSM & DCS system)and the later 3G system. According to the different requirement in other nations, some bands are still in use now, such as CDMA, PCS, PHS band, etc. With development of 3G mobile communication businesses and miniaturization of antenna, there is a higher and rigid requirement of antenna space and quality.Firstly,this thesis introduced analysis methods, character and application of EBG structure in communication microwave circuits. Then it introduced the trend of miniaturizing internal antenna design in present mobile communication. Next parts presented application of EBG structure in filter, high Q value resonator of passive MIC, giving design rules and ideas. Through simulation and measurement, design and optimization of passive apparatus had been made to validate the character of EBG structure and find EBG is more merit to miniaturization of microwave circuits.The design of miniaturizing, effective and low-profile mobile communication antenna, including plannar and monopole antenna is another emphasis in this thesis. Based on the needs of mobile telephone and fixed telephone, the thesis provided some novel type internal antenna of mobile telephone. Through simulation and measurement (Passive & Active test), the antenna was found completely satisfying the user's requirement and access validation.For the purposed miniaturizing antenna design, according to real cases and the experience of this thesis, some design rules and attention details were given. Some constructive advice to antenna space requirement and PCB layout of Feed & Short were also given. Those rules and advice gave beneficial suggestions to shorten research circle and decrease risk.