Reseach On The Ultra Bandwidth Omnidireactional Radiation Antenna With Nondivision Beam

Ultra bandwidth technical has the unique advantages on the area of solving data transmission, the shortage of spectrum resource and accurate positioning. It attract people to focus and do research on it. And it develops rapidly. Especially on the multipoint communication and signal capture, wider bandwidth and a broader range of radiation pattern means that can receive and locate more numbers of signal and the signal of wider band. As key components of the radiation and the signal reception, the performance of the antenna has a direct influence on the final result of the whole system. This paper starts from the monopole antenna and introduces some UWB omnidirectional radiation antenna with several beam that does not split. Specific work is as follows:This paper first introduces the definition of UWB and the development history and research status at home and abroad of the ultra-wideband antenna.Then some commonly used basic indicators are introduced. And give a brief explanation that how some classical ultra-wideband antennas work and how to reliaze them.2. Based on the analysis of the monopole antenna theory and the simulation of the model, relationship between the size and the bandwidth of the monopole is achieved. To ensure that the performance of the antenna does not affect, the size of the antenna is reduced.And then through the analysis on the performance of the circle monopole antenna, when the bandwidth requirements are satisfied, we find that the horizontal radiation pattern will be gradually with the increase of frequency by omnidirectional radiation into 8-shaped radiation, and the lobe distortion happens and burr and shock are produced. By fitting the radiation pattern and calculation, it concludes the final radiation pattern of the superposition of multiple antennas which has the omnidirectional radiation pattern. Then simulation is verificated. At last, flat floor structure of the antenna is instead of a tapered structure floor, while reduce the antenna size and also improved antenna radiation characteristics on the vertical direction. Also the two more forms of antenna are introduced. Finally the test proved that the return loss of antenna within the range 2-18 GHz band is less than-10 d B. And in the entire frequency bandwidth, the radiation patter of the antenna is ominidirectional and the figure is smooth.3. The model of superposition of monopole antenna is presented. By simulating the filter separation model, it proves that the superposition of multiple antennas not only can make the antenna bandwidth expanded, and the pattern can be complementary. Then a new model of ultra-wideband omnidirectional antenna is introduced. Through the changes of the feed port of antenna, the input impedance is matched. After analysis of parameters’ effect on the performance of the antenna, finally the antenna is achieved within 2-18 GHz reflection coefficient less than-10 d B, and within the entire bandwidth of omnidirectional radiation.