Chipless first generation
RFID tags that do not contain a silicon chip are called chipless tags. The first generation of chipless technologies did not meet open standards for use by many service providers and no attempt was made to write such standards for them. There were many chipless technologies offered, including acoustomagnetic, swept RF inductor capacitor arrays and electromagnetic RF sputtered film, each a multi-bit version of one of the three types of anti-theft tag in common use. Others have been in the form of diode arrays, Surface Acoustic Wave (SAW) devices and chemicals that emit high frequencies when moved. However, only acoustomagnetic tags for error prevention in healthcare and SAW tags for non-stop road tolling and manufacturing have achieved sales above one million tags.