| 摘要 |
<p>A data transmission-reception unit which operates by means of energy of a received electromagnetic wave and serves as a main circuit, is provided with a sensor circuit (130) as an additional circuit, and a transponder (100) having a sensor power circuit (150) only to the sensor circuit is constituted. From a sensor charging circuit of an interrogator (230), an electromagnetic wave of a lower frequency different from a frequency of electromagnetic wave for data communication is radiated, or loop coil-shaped charging antennas (102,202) are electromagnetic-coupled to thereby charge a capacitor for the sensor power circuit. Thereby, a secondary battery and the capacitor such as a large scale capacitor can be easily charged from an outside, and further, a power consumption for the capacitor can be restrained. <IMAGE></p> |
