Ultra-Wideband/Multiband Antenna Used For Modern Communications

Antenna is a very important wireless equipment for transmitting and receiving electromagnetic waves. With the same communication system, the performance of antennas will have an important impact on the quality of communication. Antenna plays an important role in people’s daily lives, it can be found in all kinds of mobile terminals that people using. In addition, the application of antennas is everywhere in the military field, it can be said that a good antenna plays a vital role for national security. With the development of radar, electronic warfare and modern communication technology, the constant innovation of science and technology, the expansion of radio spectrum and requirements of systems to the antenna are also getting higher and higher. So, the research and development of antenna is promoting.At present, the broadband, multi-band, miniaturization of communication antennas are main direction. Compared with traditional narrowband systems, UWB technology has a higher data rate, a stronger anti-multipath effects and lower system cost. These advantages make the development of ultra-wideband antenna more competitive. With good compatibility for multiple communication standards, multi-band antenna has developed rapidly and been the focus of industry research. Due to its small size, light, low cost, and integrated easily with microwave circuits, microstrip antenna has been more widely studied and applied.The main purpose of this paper is the design and analysis of ultra-wideband/ multi-band antenna. Firstly, it introduced the theory of antennas(basic performance parameters, multi-frequency technology and the band broadening method of microstrip antenna), starting from the background ultra-wideband/multi-band antenna. Secondly, a Ultra-Wideband Quasi Yagi antenna applied to K-band and a dual band antenna based on Yagi antenna were designed after the research on its radiation mechanism, the effects on the performance of the antenna by different structural parameters was analyzed. Finally, several models of the monopole antennas was introduced. A multi-band printed monopole antenna applied to WLAN/WiMAX was designed. The designed antennas were processed into several physical, and test results are basically consistent with the simulation results which verifys the correctness of the designs.