RFID is a flexible technology that allows businesses to close the gap between acquiring data, converting it to meaningful information, and automating all associated transactions. It can provide traceability and real-time control to meet customer and regulatory requirements while actually improving efficiency and profitability. RFID can be read-only or read / write, does not require contact or line-of-sight to operate, can function under a variety of environmental conditions, and provides a high level of data integrity. In addition, because the technology is difficult to counterfeit, RFID provides a high level of security.

Components of RFID Solution

RFID technology uses frequencies within the range of 50 kHz to 2.5 GHz. An RFID system typically includes the following components:

Transponder / Tag :

A RFID device that actively transmits to a reader is termed an "active" tag; an RFID device that only reflects or backscatters transmission from a reader is termed "passive." The tags are programmed with data that identifies the item to which the tag is attached. Tags can be either read - only, volatile read/write, or write one/read many (WORM) and can be either active or passive. In general, active tags use batteries to power the tag transmitter (radio) and receiver. These tags usually contain a greater number of components than do passive tags. Therefore, active tags are usually larger in size and are more expensive than passive tags.

In addition, the life of an active tag is directly related to battery life. Passive tags can be either battery or non-battery operated, as determined by the intended applications. Passive tags reflect the RF signal transmitted to them from a reader or transceiver and add information by modulating the reflected signal. A passive tag does not use a battery to boost the energy of the reflected signal. A passive tag may use a battery to maintain memory in the tag or power the electronics that enable the tag to modulate the reflected signal.

Antenna :

Each RFID system includes at least one antenna to transmit and receive the RF signals. In some systems, a single antenna transmits and receives the signals; in other systems, one antenna transmits and one antenna receives the signals. The quantity and type of antennas used depend on the application.

RF Transceiver :

The RF transceiver is the source of the RF energy used to activate and power the passive RFID tags. The RF transceiver may be enclosed in the same cabinet as the reader or it may be a separate piece of equipment. When provided as a separate piece of equipment, the transceiver is commonly referred to as an RF module. The RF transceiver controls and modulates the radio frequencies that the antenna transmits and receives. The transceiver filters and amplifies the backscatter signal from a passive RFID tag.

Reader :

The RFID reader directs the RF transceiver to transmit RF signals, receives coded signal from the tag through the RF transceiver, decodes the tag's identification, and transmits the identification with any other data from the tag to the host computer. The reader may also provide other functions. For example, ETC applications include accepting data from other input devices such as a vehicle detector and controlling gate and lights. Firmware in the reader controls reader operations. The user can change or customize the reader's operations to suit a specific requirement by issuing commands through the host computer or a local terminal.

RFID Frequencies

There are basically four frequency bands in which RFID works namely; LF, HF, UHF and Microwave. LF or Low Frequency is in the 100-500 KHz frequency band and provides short to medium read range at a low reading speed. Its advantages are its ability to penetrate obscuring materials and its inexpensive compared to other frequencies. Most suitable application areas are animal control, car immobilizer, access control and inventory control.

HF or High Frequency ranges from 10 -15 MHz; typically 13.56 MHz and provides short to medium reading range at medium reading speed. It's potentially inexpensive and has moderate penetration in obscuring materials. Mainly finds use in the application areas like access control, pallet and carton identification and smart cards.

UHF or Ultra High Frequency has a comparatively long read range and is available in the 860-950 MHz frequency band. It has high reading speed and is expensive compared to the other frequencies. It is ideal for applications like supply chain management, railroad car monitoring and toll collection systems.

Microwave Frequency is found in the 2.4 -5.8 GHz frequency band and has a medium read range with moderate penetration ability in obscuring materials. It's relatively expensive compared to LF and HF. Microwave is most suitable for applications like carton and pallet identification.

Typical Applications for RFID :

• Automatic Vehicle identification
• Inventory Management
• Work-in-Process
• Container/ Yard Management
• Document/ Jewellery tracking
• Patient Monitoring