US Patent 11436424 RFID-based sensing method and system

An RFID-based sensing method including receiving, from an RFID tag with a tuning circuit when the tuning circuit is arranged in a first state, a first RF signal; and receiving, from the RFID tag when the tuning circuit is arranged in a second state, a second RF signal. The tuning circuit is arranged to affect or facilitate impedance matching of an antenna and an integrated circuit of the RFID tag. The method also includes processing the first and second RF signals received to determine respective differences in two or more properties of the first and second RF signals received; and determining, based on the processing, a status associated with an environment in which the RFID tag is arranged.