| UWB(Ultra-wideband) communication technology, it has been widely used in the short distance wireless communication systems. GHz broadband transmission is one of its advantages. In the UWB communications, antenna is an important component of the signal receiver system. Thus the design of UWB antenna is a hot topic.In this thesis, firstly the history and current developmental situation are introduced, including the basic theories of the UWB antenna, the design methods of basic patch antenna, and the main process of antenna design by HFSS software. The main contents of the thesis as follows:1. Based on the study of rectangular patch antenna, a polygonal patch antenna is designed, which can match the standard 7.5GHz bandwidth civilian communications band defined by FCC(Federal Communications Commission). The bandwidth of the new polygonal patch antenna can be up to 14 GHz, with a good performance in the whole bandwidth.2. An improved structure of patch antenna is designed based on the study of polygonal patch antenna. This structure is made of a combination of circle and ellipse. Two different structures of antenna are studied. The bandwidth of the final structure antenna has been further expanded. Subsequently, the improved patch antenna is miniaturized by the method of cutting the away the weak current parts. Compared to original antenna, the miniaturized antenna performs slightly worse, but the total area of antenna can be greatly reduced.3. The band of UWB communication has some overlap with the existing narrowband communication. It will produce some interference to UWB communication. The band-notched function is designed for the miniaturized antenna. An antenna with band-notched in 3.75 GHz is designed by cutting a U-shaped slot in the radiation patch, and another antenna with dual-band-notched characteristics in 3.75 GHz and 5.5GHz are designed by two U-shaped slots. From the simulation results of band-notched antenna, it can effectively inhibit the interference of existing Wi MAX(3.3~3.7GHz), C-band satellite communications(3.7~4.2GHz), and WLAN(5.15~5.825GHz). |
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