A SAW RFID tag or sensor has an antenna for receiving and propagating an RF signal, an input/output IDT electrically connected to the antenna, and a dual track reflective IDT having a first track and a second track located adjacent and acoustically coupled to the input/output IDT. An RF signal received...http://www.google.de/patents/US7005964?utm_source=gb-gplus-sharePatent US7005964 - Dual track surface acoustic wave RFID/sensor
