| Impulse radio Ultra wideband(IR-UWB) technology are widely used in wireless communications, geological survey, radar, LBS(Location-based services) and many other fields for its high transmission speed, high resolution, strong penetration ability, strong anti-jamming capability, good secrecy, simple structure, easy to digitize, etc. This makes time-domain beam scanning array antenna based on IR-UWB technology has very wide application prospect. There is big difference between the research on IR-UWB antenna and the research on narrow band antenna based on classical frequency domain method due to the time-domain transient characteristics of IR-UWB antennas, so the research of UWB antenna in time-domain is of great theoretical and practical significance.In this dissertation, the research on time-domain beam scanning array antenna is carried on based on time-domain transient characteristics, which explore the time domain method of IR-UWB antenna analysis, introduce the IR-UWB signal waveform selection principle and the working mechanism of the beam scanning array antenna, design and optimize the IR-UWB antenna using signal fidelity and energy radiation pattern as the index, realize the joint optimization of multi-parameters in the full frequency band and in the full beam scanning range, and solve the following problems of classical frequency domain methods: frequency domain methods could neither provide the transient response variation versus time nor give out the relationship between the transient response and the characteristic parameters directly, the antenna parameter in frequency domain based on a single frequency point is not sufficiently typical to describe the antenna characteristics in ultra wideband. The main contents of this dissertation are organized as follows:(1) Time domain characteristic modeling of IR-UWB antenna. Firstly, the ideal transmission conditions of IR-UWB antenna is analyzed in methods of signal and system, and then the definitions of some important time-domain parameters such as fidelity and energy pattern are presented. The time domain characteristic modeling of the process of transmitting and receiving pulse signal is carried out. Based on the work above, the study on the time-domain characteristics of UWB antenna are carried out, including the impact to the UWB antenna fidelity of different excitation impulse signals, the antenna transceiver reciprocity and the time-domain characteristics of Vivaldi antena, which provide a theoretical basis anddata references for the subsequent research.(2) The improvement of differential evolution algrithm and generalized differential evolution algrithm. By introducing variable mutation strategy and control parameters based on optimization target threshold by stages into differential evolution algorithm and multi-objective optimization generalized differential evolution algorithm, the optimization algrithm are improved to obtain faster convergence rate and stronger local search capability, while maintaining the diversity of the population.(3) The improvement of Vivaldi antenna fidelity property in sphere space. Focusing on the characteristics of the time-domain beam scanning antenna array, a method to improve the fidelity property in sphere space of Vivaldi antenna by dielectric loading is presented. Both the simulated and measured results show that the presented method improved the Vivaldi antenna fidelity property in sphere space substantially. The improved Vivaldi antenna is quite suitable for use as an array element in beam scanning antenna array.(4) The reseach on one-dimensional and two-dimensional antenna array time domain radiation pattern characteristics. Firstly, the general methods of one-dimensional and two-dimensional time-domain beam scanning array pattern synthesis are presented. By using these methods, the pattern performance of uniform linear antenna array and uniform square antenna array with different element spacing are analyzed. Then the one-dimensional and two-dimensional time-domain antenna arrays are optimized using the improved multi-objective differential evolution algrithm presented in this dissertation. Both the simulated and measured results show that the optimized nonunifom antenna array have narrower beam width and lower sidelobe in the whole beam scanning range, which has better pattern performence.
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