Broadband Planar Slot Antenna Research

Antennas are the necessary components in the modern wireless systems. The miniature and wide band of the antennas become more and more important than before as the development of communication technology. There are not any differences in the 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 very broad band. This dissertation mainly researches the ultra-wide band planar slot antennas. Three novel planar slot antennas are proposed. Many technologies of them are discussed in theory, simulation and experiment.The first novel planar slot antenna is modified from a conventional bow-tie slot antenna. Connecting the two bow-tie slots with an annular slot and adding round corners to the modified slot, we gain a 10dB return loss bandwidth of 81.5%, from 5.18 to 12.31 GHz. Moreover, the radiation pattern of the proposed antenna gets more stable and its main beam is kept almost unchanged as the frequencies increase.The second new planar slot antenna is modified on the basis of the first antenna. We introduce some annular slots to the mental stub, which size is different from the former antenna. By these means, we gain a 10dB return loss bandwidth of 57.6%, from 6.8 to 12.3 GHz.The third antenna is a planar wide slot antenna. We introduce two round corners to the square slot, and add a gradual changed part to the feed line. By these means, the 10dB return loss bandwidth reaches 148%, from 3 to 20GHz. And the measured data agree well with the simulated ones.It is concluded from the results of this thesis that, planar slot antennas are fit for broadband working. And most of these antennas can be worked out by optimizing their geometry parameters.