Patent ID: 8947236
Filing Date: 2015-02-03
Classification: G06K

Abstract:
1. An RFID device comprising: a microchip; an antenna operatively coupled to the microchip, the antenna having a linear section and an impedance transforming section operatively coupled to the microchip and to the antenna with the impedance transforming section comprises a loop of conductor material having a pair of connection points for coupling to the microchip, the impedance transforming section transforming the microchip impedance to create a first complex reflected signal when the microchip is in a receive state; wherein changing an electrical characteristic of at least one component of the RFID device results in a second complex reflected signal at a reader device, creating a relative difference between the first complex reflected signal and the second complex reflected signal representing a sensed state of a material in proximity to the RFID device, and the changing of the electrical characteristic is controlled by varying an incident radio frequency power transmitted by the reader, and the reader measures amplitude and phase modulation of the reflected signal.