A read/write device includes a transmitter for producing an RF signal and a modulator coupled to said transmitter for modulating the RF signal and, finally a data receiver for receiving RF data signals from a portable microchip. The microchip includes a resonant circuit tuned to the RF frequency of the...http://www.google.fr/patents/US5218343?utm_source=gb-gplus-shareBrevet US5218343 - Portable field-programmable detection microchip
