Products similar to that already exist, albeit not as low power as the device in the paper. For example, this passively powered UHF RFID tag has a moisture sen

Products similar to that already exist, albeit not as low power as the device in the paper. For example, this passively powered UHF RFID tag has a moisture sensor built in: https://www.dipolerfid.com/RFID-Tags/Smartrac-Dogbone-Humidity-Sensor https://www.dipolerfid.com/RFID-Tags/Smartrac-Dogbone-Humidi...