Patent ID: 6807400
Filing Date: 2004-10-19
Classification: G06K

Abstract:
A Batteryless transponder which, in its reception phase, acquires its supply energy by the rectification of an RF interrogation pulse transmitted by an interrogation device and then stores it in a storage element serving as a supply voltage source during the transmission phase, and which, in response to the reception of the RF interrogation pulse, transmits information stored in it, wherein the coil of a tuned circuit having a resonant oscillation frequency serves as an antenna for both the reception of the interrogation pulse and the transmission of the information, characterized by a controllable switching device (14, 16, 18, 20, 22) which disconnects the tuned circuit (26) from the supply voltage source during the transmission phase, and connects it to the supply source only for a duration which is short as compared with a quarter period of the resonant oscillation frequency.