Research On Microstrip Antenna Miniaturization Techniques

Due to the rapid development of wireless communication technology,the urgent requirements of miniaturized and multifunctional terminals have been proposed. As the air interface,the antenna play a very important role in the performance of the whole system and in most cases their dimensions are the decisive factor that determine the size of terminals. Micro-strip antenna has been widely used during the recent decade because its outstanding properties of low profile,low cost,light weight,easily fabricated and easily integrated with radio frequency and microwave circuit.This dissertation mainly focuses on the researching and summarizing of micro strip antenna miniaturization technology.In the first place, the researching progress is concluded and the working mechanism of micro strip antenna is briefly introduced.The transmission line theory used to analyze micros-trip antenna and basic parameters evaluating antenna performance are also included in this thesis.Secondly, design requirements for integrated reader antenna is proposed based on the analysis of mobile phone integrated RFID reader. The application of magnetic substrate in miniaturization of micro-strip antenna is investigated. The influence of the varied material proprieties on antenna performance is studied in detail. A small sized 433 MHz RFID reader antenna based on substrate is designed. The aperture coupled feed method and rectangular shape patch makes the fabrication and integration of antenna easy. The antenna takes up only seventh space of conventional antenna,but it has a peak gain of 1.26dBi and its bandwidth covers 1.3MHz which both meet the requirements of system.In the last part, the miniaturization and multi-band methods of another kind of patch antenna,names planar inverted F antenna(PIFA) are researched.By using folded patch and etching slots on patch,a compact triple-band PIFA can be easily obtained. Antenna for GSM/DCS/ISM is presented for this method. The antenna's covers impedance bandwidths (S11<-10dB)of 30 MHz,50 MHz and 140 MHz separately at the three bands.The antenna has a volume of 27 X 25 X 7mm3,about two fifths of conventional PIFA antenna. The resonant frequencies can be easily tuned independently by change the corresponding parameters.