Miniature And Multi-band Antenna Design

With the continuous growth of mobile communication service and the constantminiaturization of communication equipment,there are higher and higher demands forthe volume,integration and working band of antennas．The main task of this thesis is todesign and study the miniature multi—band antennas．Firstly,the history of the miniature multi—band antennas has been reviewed,thedevelopment of the miniature multi—band antennas, research background and the latesttechnology have been introduced in the dissertation. Secondly,the basic theoretical andanalytical methods using to analyze miniature multi—band antennas have beenintroduced,including classical theoretical methods and some of the popular numericalmethods．The technique for compact and multi-frequency antennas have also beensummarized in this dissertation．Finally,two compact miniature or multi-frequencyantennas have been proposed．The first antenna, crossed field antenna, owns the features of compact structure,small floor space, high efficiency, wide band and easy to achieve high-speed digitaltransmission in MF. By the use of ansoft HFSS and ansoft Designer cooperative designplatform, the results from 3D-EM simulation are linked into the circuit simulation andone 26 percent of the wavelength high and 26MHz~33MHz tunable CFA is achieved.The second antenna is miniature dual-band microstrip antenna. The basic theory and thetechnique for compact and multi-frequency of microstrip antenna has been summarized.A ratio tunable dual band microstrip antenna is offered too. The first order cross-shapedslot-coupled and the second order cross-shaped slot-coupled miniature dual-bandmicrostrip antenna is designed.