A product tagging system is provided. The product tagging system includes at least one RF backscatter transmitter configured to emit (i) a main carrier RF signal, and (ii) Radio Frequency (RF) signals on two frequencies whose summation forms a twin carrier RF signal. The product tagging system further includes a passive RF backscatter tag associated with a product and configured to reflect and frequency shift the main carrier RF signal to a different frequency using the twin carrier RF signal. The product tagging system also includes at least one RF backscatter receiver configured to read the product on the different frequency by detecting a distributed ambient backscatter signal generated by a reflection and frequency shifting of the main carrier RF signal by the passive RF backscatter tag.