THICKNESS MEASURING APPARATUS

摘要

PROBLEM TO BE SOLVED: To measure the thickness highly accurately through a simple constitution and to display the image of received wave accurately by fixing an antenna spacer having dielectric constant identical to that of an object to be measure at the antenna section. SOLUTION: An antenna spacer 3 fixed to an antenna section 2 is composed of a substance having dielectric constant identical to or substantially identical to that of an object to be measured (pavement 10). The thickness (h) is set in such a range that an electromagnetic pulse wave can be transmitted/received sufficiently up to the boundary face between the pavement 10 and the roadbed 11 through the spacer 3. When an electromagnetic pulse wave having narrow width is transmitted from a transmitting antenna 104 and the reflected wave is received, a receiving waveform 12 is obtained. In other words, the electromagnetic wave is reflected on the boundary surface of different dielectric constant and it is not reflected on the surface between the spacer 3 and pavement 10 having identical dielectric constant. Consequently, the surface reflected wave 121 is combined with a reflected wave 122 from the boundary surface to produce a receiving waveform 12. The distance is determined from the time difference and the thickness of pavement 10 is determined by subtracting the height (h) from the distance.