Study And Design Of Compact And Wideband Microstrip Antennas

Recently, due to the trend of high-rate, high-capability, multi-function of wireless communication system, as an important component of wireless communication system, antenna has been developed a lot especially in aspect of design technology, which mainly contains the dimension reduction technology, wide band technology and intelligentized antenna technology etc. Microstrip antenna has been applied widely because of its remarked strength, however, the respective narrow band-width is always one of its disadvantage. Thus, to widen the bandwidth and minimize the dimension is one of the difficulties of the microstrip antenna design technology in the proceeding of microstrip antenna design.The thesis mainly focus on the wideband microstrip antenna research, study the minimization of antenna and the method of widen the antenna by the way of theory analysis and numerical simulation. Finally, a novel structure of dual-frequency microstrip antenna and a novel monopole UWB microstrip antenna are designed respectively. The main work of the thesis includes:1. Illustrating the design principle and method of wideband microstrip antenna, from the view of current distribution, discussing the method of current path and resonant characteristic, and a novel dual-frequency slot-microstrip antenna, the bandwidth of which is between 1.75GHz and 2.28GHz, was designed and can be used in the third generation communication.2. The description of surface current at resonant frequencies of 1.80GHz and 2.15GHz and the radiation pattern are presented and analyzed.3. Proposing and designing a novel monopole UWB microstrip antenna, the structure of which is designed as a ladder-shape, and the parameters were optimized, finally the assumed antenna was realized and the character meet the FCC standards well. In addition, the antenna has three resonant frequencies:4.35GHz,7.95GHz and 10.4GHz, and the S11 were -22.3dB,-25.8dB and -22.8dB respectively.4. Analysis and simulation of the influences of the structure parameter of the novel UWB to the antenna performance, the description of surface current at different resonant frequencies and radiation pattern are also presented and analyzed. Finally, prototype of the antenna was made and tested, test report and simulation report were compared and analyzed.