Abstract: Systems and methods for use in reading and locating passive RFID tags. A reader/locator system sends out a signal with varying frequency. A tag reflects the signal back and the receiver portion of the reader/locator system receives the signal after a certain propagation delay. Since during this propagation delay the transmit frequency has changed, the received signal frequency differs from the one is currently transmitted. The received signal gets mixed with the currently transmitted signal and the resulting beat frequency depends on the frequency variation pattern (which is known) and the signal propagation delay. This beat frequency is directly proportional to the distance between the reader/locator and the RFID tag. The beat frequency can therefore be used to estimate this distance between the reader/locator and the RFID tag.

Abstract: Plasma treatment apparatus includes means to generate a plasma jet at atmospheric pressure, and means to control both the cross-sectional size of the jet and the relative speed of movement between the jet and a body being treated.