Stepped Frequency Continuous Wave Through The Wall Radar Transceiver Front-end Development,

The UWB (Ultra wide band) through-the-wall radar is a new techology of radar- exploration, which penetrates the wall and other opaque obstuctions by sending super broad band electromagnetic wave, can be used in detection, orientation and imaging of the targets. The following research work is done concerning this point:1.Introduce the history of development of through-the-wall radar and status quo of the research work in the related research institution of China.2.Expatiate the principle and work mode of the stepped-frequency through-the-wall radar, based on which and the hardware design scheme is discussed . Firstly one kind of design scheme had been assumed, in which the system is composed of an up frequency transform transmitter and a superheterodyne receiver. Then the phase difference of transmitting signal and local osillating signal in this scheme is demonstrated, So the zero-IF system is used to deal with this problem.3.The function realization of transmitter on the through-the-wall radar hardware system is analyzed in details. The stepped-frequency transmitter with bandwidth 1GHz~2GHz is designed using integer divider PLL.The power fluctuation are less than 2dB in bandwidth. And a method is proposed to judge if the PLL is locked utilizing oscillograph and dismodulator.4.The advantages of the zero-IF receiver have been shown, as well as the better performance in DR,NF in theory than the superheterodyne receiver. Design the receiver based on passive mixer and active mixer, including the signal channel, the base-band filter and the AD circuit design and realization. Specially, we propose some useful perspective in Quadrature Demodulator AD8347 design.5.Finally, the test result is given. It indicates that the front-end of the radar satisfes the requirements of the signal processing.