A global SAW ID tag with large data capacity

The Global SAW Tag uses a recently-invented digital modulation based on simultaneous time position and phase shifting. A unique feature of this tag is that it satisfies global RFID requirements using the international 2.44 GHz ISM band. Precision amplitude and phase weighting of reflectors and accurate control of parasitic effects is critical to implementing this device. This tag has significantly more data bits, lower insertion loss, and smaller die area (i.e. lower cost) than previous SAW tags. These improvements eliminate the shortcomings that have previously limited the market for SAW RFID (radio frequency identification). A 2.44 GHz fundamental mode tag on 128/spl deg/ LiNbO/sub 3/ with 64-bit data capacity plus 16-bit error detection coding is described.