| Following the widespread application of modern wireless communication system in various fields and the boom of various kinds of information transmission technologies, the performance of antenna, a key component in the system, has a direct bearing on the overall quality of the system. The microstrip slot antenna, featuring small volume, low profile and high integration, favorably meets the development requirements and trend for modern wireless communication system. Therefore, the microstrip slot antenna boasts great research significance. This paper centers on the microstrip slot antenna with specific procedures as follows:Firstly, this paper has described the background and research significance of the microstrip slot antenna, analyzed the development status at home and abroad as well as relevant technologies, and then introduced the classification, basic performance parameters of microstrip slot antenna and related theories of EBG structure. Finally, one type of miniaturized broadband microstrip slot antenna and two types of microstrip slot antennas with band-notched characteristic are designed.Secondly, a microstrip slot antenna featuring gradient meander feed source is proposed against the miniaturized broadband microstrip slot antenna. An analysis of design thought and the relationship between the structural parameters and performance of antenna have been made and studied separately. The final simulation result indicates that the antenna with |S11|<-10 d B operates within the VHF/UHF frequency band between 249 MHz and 482 MHz. Omnidirectional radiation pattern and stable gain of the antenna can be obtained within the whole bandwidth range.Finally, during the study of ultra-wideband(UWB) microstrip slot antenna with notch characteristic, two types of UWB slot antennas assembled with compact combined bandnotched structure are proposed to avoid interference caused by narrow band communication system, such as Wi MAX and WLAN, to UWB communication system. One of the antennas applies a polygon slot as its radiating element and is fed by gradient T-shaped microstrip line. The dual band-notched characteristic is achieved by a pair of parasitic element added in the wide slot and the combined band-notched structure in the four arms spiral slot etched on the ground plane. With respect to another antenna, the dual band-notched characteristic is achieved by adding mushroom-like EBG structure near the feeder and the combined bandnotched structure in the four arms spiral slot etched on the ground plane. The simulation result shows that the bandwidth of the two type of antennas with VSWR<2 are covering 2.67 GHz to 12.3 GHz and 2.7 GHz to 12.32 GHz respectively, exceeding the civil UWB communication system specified by FCC. Better filter property is achieved during the range of 3.3 GHz to 3.7 GHz and 5.15 GHz to 5.825 GHz. Meanwhile, Omnidirectional radiation pattern and stable gain of the antenna can be obtained within the whole bandwidth range. |
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