New Planar Ultra Wideband Antenna Research

Antennas are the necessary components in modern wireless systems. Their function is to transmit and to receive radio wave. Antennas transmit the guided microwave into the free space in the frond-end of a transmitter, and do an inverted transition in the front-end of a receiver. Consequently, signals can be transmitted between two arbitrary points. There are not any differences in radiation theories between the ultra-wide band antenna and the ordinary narrow band one, but the former is developed based on the latter. The main content of the subject on the ultra-wide band antenna is to explore the novel theories, techniques, and methods to research them in a very broad band.The first chapter of this thesis is attached more importance on several parameters to describe the performance of ultra-wideband (UWB) antennas, a few ordinary types of UWB antennas and their main analytical methods.The main content of chapter II describes the positive influence of rounded corners on keen vertexes of wide slot antennas and bowtie ones. A great deal of experiments and simulations prove the conclusion mentioned above. As far as the wide slot antenna is concerned, a broad S11≤-10dB frequency bandwidth of 158% and an operating frequency band of 1.9~16.25 GHz are produced by applying this method to it. As far as the author knowledge, the most board S11≤-10dB bandwidth of 130% is seen in the presented papers. For bowtie antennas, this method can produce a better return loss in the higher frequency band than the original ones, and at the same time, the radiation pattern bandwidths of the new antennas can be broadened more or less. This method rounding the keen vertexes on the plane antennas fits for not only wide slot antennas and bowtie antennas but many other plane ones. The method is not applied first in the thesis; however, the foregoing papers did not do some summarizations on it. Therefore, this method is supported by a few presented papers and the author's three accepted papers in the International Conference on Ultra-wideband (ICU2005), Progress in Electromagnetics Research (PIER) and IEEE Antennas and Wireless Propagation (AWPL), respectively.