Study And Design Of Microstrip Antenna

Due to the development of the large capacity, broadband feature and intelligence in modern communication system, the technology of microstrip antenna advanced quickly. As the air interface,the antenna plays a very important role in the performance of the whole system and in most cases their dimensions are the decisive factor that determine the size of terminals. Microstrip antennas is the most typical frequently used in modern times.Microstrip antenna has many good characteristics of thin section plane,small volume, easily manufacturing and matching with other shapes easily,easily getting ground polarize,bi frequency-band, and bi -frequency band,and bi-polarizes. So they are used in many fields such as radar, missile observing and controlling, electronic counter measure, weapon detonator, remote sensing telemeter measurement, satellite communication, mobile communication, medical microwave, etc. But the bandwidth of microstrip antenna is very narrow. Its ordinary impedance bandwidth only 0.6%～3%, can not meet the requirements of modern wireless radio system.Four methods of enhancing the bandwidth of microstrip antenna are introduced: reducing the Q in the equivalent resonant circuit, adding extra resonant point, additional impedance matching networks, and changing the structure of the antenna. With the Ansoft HFSS, two kinds of broadband microstrip antenna has been designed. Experimental results show the correctness of design, and ensure the stability of the other performance of the antenna.More study will be carried on the widening the technology of impedance bandwidth of microstrip antenna in the future.