The Study On Soil Water Content Sensor Of One Pin Probe And Application Based On Microwave Measure Theory

This thesis studies on a soil water content sensor of one pin probe based on the principle of standing- wave ratio.First,it illustrates the principle of microwave transmission line theory and measuring medium dielectric constant with standing wave,and proves the feasibility of measuring soil water content with standing- wave ratio.On the basis of theoretical analysis,we design a soil water content sensor of one pin probe. Compared with the sensor of multi-pin structure,it can measure soil water content one point or different points of different layers.The thesis mainly study of the transmission line impedance matching and calibrated the sensor through the TDR measurement.Experiments show that the sensor has a good performance of veracity,stability and consistency.In order to verify the practical value of the sensor,it has been applied in the Olympic project "National Road" Garden Irrigation Project,based on the long-term observation in the laboratory test.In the application,the data indicate that the sensor can run stably and has good veracity.