Study And Design Of UWB Through-the-wall Radar Antenna

Through the wall radar system can detect and locate the signs of life,under complex environment,such as opaque obstacles.It plays a very important role in the city's terrorist attacks,kidnapping and fire rescue.Through the wall radar of impulse system is a kind of penetrating radar,which has the advantages of strong penetrating ability,strong anti-interference ability,good concealment performance and high range resolution.As an important part of the radar system,the antenna has a direct impact on the performance of the radar system.Therefore,it is very important to design a better antenna,which is also the goal of the paper.The main work and contents of this thesis are as follows:Firstly,it's briefly analyzed and summarized that the background and practical significance of through the wall radar system.Ultimately it's determined the frequency of 1.5 GHz~4.5 GHz Gauss pulse loading 3 GHz sine wave signal as a radar signal,through the research and analysis of the 1 GHz~10 GHz band signal on the wall penetration capacity,the system volume,radar signal waveform and impulse system.The wall radar signal is known as the UWB signal,by analyzing the frequency domain of the signal.It is analyzed that the antenna is suitable for this kind of through wall radar.This paper briefly introduces the method of extending the bandwidth of micro-strip antenna,and introduces and compares several kinds of ultra wide band antennas.Finally,Mono-pole antenna with tapered slot and the Vivaldi antenna are considered as the research of the system.This paper briefly introduces the principle,development and feeding structure of Vivaldi antenna,which is used for the design of this paper.Secondly,Mono-pole antenna with tapered slot is designed,which is suitable for wall penetrating radar.One advantage of the antenna is its small size and its volume is50% of the volume of the Vivaldi antenna designed behind it,and the high frequency characteristic of the micro-strip slot antenna is very good to 11 GHz.By analyzing the time domain characteristics,it is shown that the antenna has good time domain characteristics.Finally,it is analyzed and calculated in detail that the structure and design process of the Vivaldi antenna.The design mainly includes the calculation and design of thefeed structure and exponential tapered slot of the radiator.Then the overall performance of the antenna is described and analyzed.The return loss,radiation pattern,the peak gain,the time domain radiation waveform,the ringing phenomenon,the time domain pattern and the fidelity coefficient are analyzed.By comparing the performance of these two antennas,the Vivaldi antenna is chosen as the transmit and receive antenna of the through the wall radar system.At the same time,a one-dimensional linear array is constructed to simulate the synthetic aperture,and the parameters of the array are studied to determine the position of the receiving antenna.