Research Of A Novel Ultra Wideband Antenna Technology

The ultra-wideband communication technology is a novel wireless communication technology which transmits signals with short pulse, and usually the pulse can cover a very wide frequency band. As a result, the ultra-wideband antenna must be able to radiate and receive the short pulse signals without distortion, in other words, the ultra-wideband antenna has to own several octave impedance bandwidth or more, and stable phase center, which enables the ultra-wideband antenna to transmit and receive short pulse signals without distortion.The circular monopole antenna is a kind of miniaturized and easy-feed ultra-wideband antenna. The circular monopole ultra-wideband antenna has not only the extremely wide band in frequency domain, but also stable phase center, which makes the antenna radiate and receive the short pulse signals without any distortion, and suitable for various ultra-wideband communication systems or the single antenna of other multi-frequency operating communication systems.Firstly, the differences between the ultra-wideband antenna and conventional wideband antenna are introduced in this thesis, and the definitions of several performance parameters of the ultra-wideband antenna are presented, among which the phase center and the group delay time are primarily discussed in that they describe the time domain properties of the antenna. Also, the concept and common research methods are introduced in this thesis.Secondly, through the electromagnetic simulation, the impedance and radiation properties of the circular monopole antenna are thoroughly analyzed. And the design method of the circular monopole antenna is presented. Then the influences of the dimension parameters on the impedance property and radiation property are studied, and the relationship between the feed height and the impedance property is presented. Also, the wind load and radome problems are discussed by simulation. Then on the basis of former studies, the miniaturization and planar structure of the circular monopole antenna are respectively analyzed and two feasible schemes are presented.At last, two circular monopole ultra-wideband antennas with different radius are made. By experiments, the return loss, radiation pattern and gain of the...