The Research And Design Of The Transmitter And Receiver For Multi-frequency Impulse Ground Penetrating Radar

The impulse ground penetrating radar(GPR), transmitting nanosecond or subnanosecond pulse, whose frequency band spreads from DC component to several GHz and reflection contains rich information of the target, so impulse GPR can identify targets varies from concrete to utilities underground and some tombs deep inside the ground, is a very useful method with varieties of applications. The targets of GPR are widely distributed underground and varies in shapes. To detect different kinds of targets require different ranges and resolutions, three kind of pulse signals with different frequency band were chosen. And the transmitter and receiver of impulse radar were researched and designed. The may works are as follows.1. The principles and structure of the impulse GPR were researched, including calculating the parameters of GPR and designing the structure of the impulse GPR.2. The pulse generator for impulse GPR were designed. The parameters of the pulse for three kind of radar with the model of Gaussian pulse were calculated, the pulse generator with avalanche transistor and step recovery diodes were designed.3. Ultra-wideband antennas for GPR were designed and simulated. The antennas include bow-tie antennas and a TEM horn antenna were designed.4. The low noise amplifier, and sample/hold amplifier and choose a programmable gain amplifier were Design.The impulse GPR works with two antennas which means the transmitting antenna and receiving antenna working independently. The receipt signal of antenna is amplified through low noise amplifier(LNA) and acquired by sample/hold amplifier(SHA) in the way of equivalent sampling to save the cost of an high-speed analog to digital converter, and cut off the extremely demands of hardware for high-speed data transmitting. Then it is amplified by a programmable-gain amplifiers to avoided ignoring small reflections from deep levels.