Sensing properties of a material loading a UHF RFID tag by analysis of the complex reflection backscatter at different frequencies and power levels

摘要

An RFID device for sensing the properties of a material in proximity to a UHF tag. The RFID device includes a microchip, an antenna operatively coupled to the microchip, and an impedance transforming section operatively coupled to the microchip and to the antenna. Changing an electrical characteristic of at least one component of the RFID device results in a complex reflected signal at a reader device representing a sensed state of a material in proximity to the RFID device.