How Swept-RF Works
Swept-RF uses a transmitter to create a detection zone where tags are detected. The transmitter sends a signal that varies between 7.4 and 8.8 MHz (millions of cycles per second), which is why it is called swept; it sweeps over a range of frequencies.
The transmitter signal energizes the swept-RF tag, which is composed of a circuit containing a capacitor and a coil, both of which store electrical energy. When connected together in a loop, the components can pass energy back and forth or "resonate."

The tag responds by emitting a signal that is detected by a wideband receiver, meaning a receiver that monitors for signals over a wide frequency range; for swept-rf systems the bandwidth is typically about 1,400,000 Hz. By detecting a phase difference between these two signals, the receiver recognizes the presence of a tag, and it alarms.