| 摘要 |
A method for readily calibrating the relative permittivity of a electromagnetic detector before detection, and an electromagnetic detector using the relative permittivity calibration method are disclosed. An electromagnetic detector (1) comprising a transmission antenna (T) for radiating an electromagnetic wave, a reception antenna (R) for receiving a reflected wave of the radiated electromagnetic wave, a reception unit for generating a reception signal in response to a detection signal from the reception antenna (R), and a signal processing unit (10) for processing the reception signal and outputting an analysis signal in which the signal processing unit (10) has a period adjusting section (10d) for converting the reception signal to the analysis signal having a different signal period by frequency conversion, and the period adjusting section (10d) has a setting means (10e) such as a variable capacitor for setting a frequency conversion constant, wherein the setting means (10e) is adjusted so that the period of the analysis signal when an electromagnetic wave is radiated into the air from the transmission antenna (T) may agree with the reference time t predetermined according to a reference relative permittivity.
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