一种新颖的适用于探地雷达应用的平衡脉冲发生器

A Novel Balanced Pulse Generator for GPR Application

介绍了一种新颖超宽带皮秒级的脉冲发生器。该发生器由雪崩三极管电路和独特的脉冲整形电路构成。雪崩三极管电路产生一对平衡的驱动脉冲信号,脉冲整形电路有效利用阶跃恢复二极管的阶跃特性产生一对平衡的快前沿脉冲信号。从测量结果可知,当脉冲重复频率为1 MHz时,该脉冲发生器输出一对峰值电压为±30 V的平衡脉冲,前沿约为260 ps,而后沿相对较缓,且具有极小的振铃。当该发生器给偶极子天线馈电时,接收的信号拖尾极小。在探地雷达浅层探测中,该脉冲发生器可以实现多目标高分辨率检测,具有很好的应用前景。

A novel ultra-wideband（UWB）picoseconds pulse generator is described in this paper. It contains an avalanche tran-sistor circuit and a unique pulse shaping circuit. The avalanche transistor circuit can produce a pair of drive pulses. The pulse shapingcircuit utilizes the transition characteristics of step recovery diode（SRD）effectively to generate a couple of balanced pulses with veryfast leading edges and high amplitude when the pulse repetition frequency（PRF）is up to 5 MHz. Measurement results show that thepeak voltages of the output pulses are approximately ±30 V at 1 MHz PRF,and both of the leading edges of the output pulses are ap-proximately 260 ps while the trailing edges are relatively slow with very small ringing. When it offers feeding to a dipole antenna,its re-flected wave nearly has no trailing. Therefore,this novel pulser can ensure high range resolution and fine penetration capability for ap-plications in ground penetrating radar（GPR）,especially for the shallow detection.