Beyond Bar Codes: Tuning up plastic radio labels Peter Weiss Electronic labels made from plastic semiconductors can now pick up and respond to radio signals at a frequency suitable for use on products. At an electronics conference in San Francisco this week, two European industrial-research teams described plastic radiofrequency-identification (RFID) prototypes with those advanced capabilities. Although silicon-based RFID tags are already in wide use—for instance, in so-called smart cards used to pay mass-transit fares—the new developments bring closer the prospect of RFID tags becoming as common as bar codes, or perhaps even more so, the researchers say. Besides labeling consumer...