Thresholds for the Identification of Commercial Wireless SAW ID-Tags

Passive Surface Acoustic Wave (SAW) sensors intended to measure different physical quantities are often manufactured to have Radio Frequency Identification (RFID) tags with time position encoding. The optimum threshold is proposed for the identification of commercial SAW ID-tags. We first find the generic identification error probability for such tags employing the Marcum function of first order and then minimize it in order to find the optimal threshold. The results are obtained for the ideal conditions of equal 30 dB SNR. As examples of applications, we give the estimate number of reflectors for an ID error probability lesser than 1 and 0.1% (1 slip per 100 and 1000 readings).