| In recent years, along with the continuous development of wirelesscommunication systems, new technologies and new standards in wirelessapplications are coming out one after another. These not only satisfy the demand onwork and life of people but also greatly promote the development of wirelesscommunication technology and related products. At the same time, the vigorousdevelopment of wirless communication puts forward higher and higher demand onwireless communication equipment. As the volume of the communication equpmenthas been declining, the antenna,as a key part, faces the problem how miniaturize it.Wide band of the communication equipment promotes the development ofwideband antennas。In this paper，the research background and research status of electrically smallmicrostrip antennas is introduced. And then the technology of the microstripantenna miniaturization， such as antenna loading， meandering technology，additional active network，are researched. Besides, some band width enhancementtechniques of microstrip antenna are analyzed, such as parasitic element structure,the layered structure, wedge or ladder-shaped structure, and the impedancematching networks.A novel coplanar waveguide (CPW)-fed monopole antenna that can be used forWLAN application is designed. According to the widened technology research，themicrostrip antenna is fed by CPW instead of microstrip line. Therefore, it becomesa ultra-wideband antenna, whose frequency band can cover WLAN. A method forcreating band notches in ultra-wideband antenna is described. By introducing wideslot and asymmetric tapered structure，the antenna not only be made insensitive tothe frequencies of WiMAX, but also not have an affect on the frequencies ofWLAN. In addition, the antenna’s volume is reduced by24.3%by using theminiaturization technology.A general microstrip antenna is optimized. The floor of ladder-shapedstructure is used. Therefore, the FCC suggested bandwidth of3.1-10.6GHz issatisfied, and the antenna is also miniaturized. |
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