A differential wireless sensing device comprises a first resonant device (900) impinged on a substrate having a predetermined natural frequency, the first resonant device having a changeable resonant frequency in response to an environmental condition, and an second resonant device (905) impinged on...http://www.google.com/patents/US20050033819?utm_source=gb-gplus-sharePatent US20050033819 - System and method for manufacturing wireless devices
