RFID tags are used to wirelessly obtain ID information from objects in the environment. RFID readers typically analyze a tag's response signal and extract the ID information. Most business processes just focus on the ID and discard the tag signal properties like backscatter signal amplitude, operating frequency and phase. In our research, we manipulate these signal properties to encode sensing information. For example, what if crossing a temperature threshold snapped off part of an RFID tag's antenna and caused a massive drop in signal amplitude, or what if a change in moisture content changed the operating frequency of the tag?
The research challenge is achieving a transduction between the parameter of interest and the signal properties of an RFID tag. This is achieved using novel electromagnetic structures and the use of electrically responsive smart materials.