Research And Design Of Fractal Antenna For Mobile Devices

In the past few years,with the rapid development of communication technology,especially in the wireless communication technology,Various kinds of communication terminal also emerge continuously,It more and more towards miniaturization and complicates to develop with the direction of scale indirectly. the miniaturization of the communication equipment calls for miniaturized antennas, while the development of communication standard puts forward the development of multiband and ultra-wideband antennas.the advantage of UWB Antenna is ultra-wideband,it coverd wide frequency band range which decreased the antenna number of communication equipment,meanwhile,which modified the performance of electromagnetic compatibility,in the other hands,multiband antenna can work appointed frequency bands to decrease the distraction.improved the performance of receiving sensitivity.Therefore,the research of antenna is compact antenna,multiband antenna,UWB antenna at present.Many methods was proposed to achieve the compact multiband characteristics of the mobile terminals`antennas.It included PIFA,monopole antenna,microstrip antenna and so on.these antennas have merits and demerits at the same time.this dissertation proposes some antennas based on Hilbert curve and Sierpinski arrowhead fractal structure,because of its self similarity and space filling,the designed antennas have smaller electric size than others and multiband characteristics.In this thesis,two fractal antenna used in mobile teminals are proposed,the one is work GSM850,GSM900,DCS,PCS,WCDMA simultaneously,the other one can receive communication signals from WLAN/WiMAX applications.the paper is divided into three parts.in the first part,the principles of microwave chamber and the parameter of measured mobile devices in the chamber.In the second part,the designed antenna which based on Hilbert curve fractal structure can received communication signal in the GSM/WCDMA frequency bands,and test it,and then,a compact quasi-sierpinski arrowhead antenna works in the WLAN/WiMAX application was designed,in the last part,the design of antenna match network is researched,which is an significant content of antenna design.A viable match network design has been introduced and the L-type match network has been acquired,the results show that the integrated fractal antenna design is necessary and feasible.The dissertation provides a useful reference for the fractal antenna of mobile terminals.