RFID (Radio Frequency Identification) is a system consisting of a radio transponder, receiver, and transmitter. When an RFID reader emits an electromagnetic interrogation signal, the tag responds by transmitting digital data, typically an identifying inventory number, back to the reader. This technology allows devices to read information contained in a wireless tag from a distance without physical contact or requiring a line of sight. Passive RFID systems use tags powered by the electromagnetic energy from the reader, eliminating the need for internal power sources, making them battery-free and more cost-effective. RFID is widely employed in applications such as supply chain management, human tracking, access control, and smart labels.