| 摘要 |
<p>Method for remotely determining a type of material (21) related to transmitting a first radio signal, from a tranceiver (5), to a reflective material (29), receiving a first reflection of the radio signal reflected via said reflective material (29), providing the material (21), of which the type is to be determined, transmitting a second radio signal (17) through the material (21) of which the type is to be determined, receiving, by the transceiver (5), a second reflection (15) of the radio signal, reflected via the reflective material (29), determining a dielectric constant of the material (21) based on a time difference between the transmitting of the first radio signal and receipt of the first reflection, a time difference between the transmitting of the second radio signal and receipt of the second reflection (15), a thickness (d) of the material and a speed of light, determining, by a comparison unit (9), the type of material (21) based on the determined dielectric constant.</p> |
