How do RFID tags distinguish which part of the signal transmitted by a reader should energize a chip and what part contains information to be written to that chip?
I am not an RF engineer, but I believe that the radio waves transmitted by a reader antenna provide both energy and information at the same time, with the RF energy transmitted in waves. The energy harvested by the antenna is stored briefly on the chip, which interprets the pattern of the waves being received and responds to commands from the reader to either store data in memory or respond back with a serial number and the stored data. Any RF engineers reading this are invited to confirm my response or provide clarification below.
—Mark Roberti, Founder and Editor, RFID Journal
Can a Single Tag Be Connected to Two Antennas? »