Research On The Design Of Ultra Wide Band Bipolar And High-voltage Pulse Generator

As a new and effective detection equipment for shallow underground target,ground penetrating radar is widely used in many areas like traffic facilities detecting,glacial ice detecting and geological survey.This technology attracts a wide spread attention in engineering fields because it has lots of advantages such as quickly response,strongly anti-jamming performance,high resolution and setting in motion easily.Antenna system is the key component of ground penetrating radar and the impulse source is the key component of antenna system.As a launching system of the antenna system belongs to the ground penetrating radar,it requires the impulse signal has no DC component from feeder to itself.in the same time,the ground penetrating radar should have high quality detection resolution and sufficiently far detection distance.So the impulse signal has ultra wide band characteristics and high amplitude characteristics.This impulse signal must be ultra wideband bipolar high voltage narrow pulse.In the practice design,the Gauss function is exactly like a bell and it is easy to produce.So the Gauss function signal is suit for the launching antenna of ground penetrating radar.A first order Gauss function signals have positive and negative polarities,symmetry and no DC component.The concentrated energy makes simple construction of the circuit.Now there are some methods to produce ultra wideband bipolar high voltage narrow pulse.They are pulsed power technology,Step recovery tube technology,pulse forming line technology and RC differential circuit technology.They also have defects.This paper presents a method to produce ultra wideband bipolar high voltage narrow pulse based on the theory of transmission lines and aggregate parameter theory.First it presents a impulsive equation based on circuit modeling and gets a simulation pulse waveform from matlab.In this design,I try my best to use the simplest components and reasonable energy storage elements to avoid introducing distributed parameters.And I get a optimal and differential network.After the impulse system goes through the passive shaping optimization network,its front and rear optimization turn coincident.And then it will goes through the LR differential network and it will be the bipolar pulse.Finally 8-leave,16-leave,24-leave,32-leave avalanche circuits will be machining.I test the final result.The experimental platform has been set up for testing the impluse circuit,and a smooth waveform with perfect symmetry is obtained from the result.The amplitude is in the range of 130V~150V and the pulse width is between 3.6ns and 4.6ns.A pulse source is designed in this paper will be of great significance in the resolution and the detection range of the ground penetrating radar.