RFID Technology

Radio Frequency Identification (RFID) is an automatic identification technology that uses radio frequency without human interactions. The frequency bands used currently vary over different countries. For example, Hong Kong SAR has approved, in April 2005, two bands 920-925 MHz and 865-868 MHz for RFID use. The band in between is currently used for other telecommunication device (in this case, GSM). This is typical of few other countries that the allocated frequency bands are split or just one of the two as that in Hong Kong.

Anyhow, RFID has been used for a long time since WWII but not until recently, its applications were generally found in vertical markets with proprietary technologies. With the advent when the matured barcode system started to run out of numbers and the call for higher efficiency in a supply chain, a research group in MIT sponsored by a number of technology companies and industrial giants like Gillette and P&G set up the Auto-ID center in late 1999 with the ambition to create the next-generation asset-management system using RFID and the concept of a number that can be uniquely identifiable in the world. The outcome is a set of RFID standards and the Electronic Product Code (EPC). These technologies were then transferred to and commercialize by the non-profit making organization EPCglobal Inc. in October 2003.

At its early stage, RFID is not intended to replace the bar code system. Under the EPCglobal picture, a RFID system has 3 components, the reader, the tag and the support information infrastructure. By using the minimalist approach, the tag contains only the EPC information which would occupy 64 or 96 bits of memory space in the current generation and keeping the price to its minimal. Information related to a specific EPC will then be stored in the information infrastructure and this creates an internet of things. With the upcoming 256-bit version, it has been claimed that the numbering system is large enough to assign each molecule on the Earth a unique number. The immediate problem is to ensure most, if not all, existing trade codes offered by different standards organization, can be encapsulated within EPC. It will take some times before a consensus and a final blueprint can be reached for global trade.

A tag is an electronic device that is used to attach to movable items. There are two kinds of tags, active and passive. An active tag has its power source built-in and because of this, the tag has the capability to transmit a signal to a longer distance, generally in hundred meter range. And because of a more constant supply of power, an active tag generally has more logics or intelligence built in. This enables it to do tasks like encryption and data collection. The downside of an active tag is its physical size and limited life-span, due to the battery. On contrary, a passive tag derives (or harvests) power from magnetic induction or radiate the modulated incoming electromagnetic waves by power reflection via its antenna. No battery is built onboard. This gives the tag a very long life span but due to the limited strength of the power that the antenna can radiate, a passive tag can only transmit up to 5 meters using the 915MHz frequency band and down to only a few centimeters when using the 13.5MHz band. Physical construction of a tag consists of a chip, an antenna and the inlay. The chip is the place where information in digital form is stored. Size of the chip is proportional to the number of logic gates on it. The more the number of logic gates, the bigger is the chip size. The physical appearance of the chip is as small as a grain of sand. Some may even be described as dust.

Antenna on a tag is for receiving and transmitting signals. It is the size of the antenna that determines the size of a tag. Antennas can be designed to suit specific applications and environments. On passive tags using magnetic induction as the method for power delivery, the strength of power that can be induced on a tag depends on the effective area the antenna exposed to the power generating field. Tag antennas are manufactured by copper etching process or printing process and they are attached to the chip with the physical support of the inlay. Due to the cheaper cost, passive RFID tags will be the used for item tagging in supply chain applications.

A RFID reader is an electronic device that sends command signals to and read back the emitted signals from tags. If the tag is a passive one, the reader is also responsible to deliver the magnetic field or the source of the reflected power. If a reader has the capability to write data to writable tags, it is called as an “interrogator”. A reader has an antenna or an antenna system. The power emitting capability of the reader determines the longest distance that a passive tag signal can be read. Generally, the maximum power that can be radiated by a device using the ISM bands is regulated by government. For example, in USA, FCC allows the maximum radiated power up to 2W before a special license is required. Under such condition, sensitivity of the reader in turn determines the maximum distance where a passive tag signal can be detected reliably. After reading the tag data, the reader will pass it to the backend support system for intended purposes.

The significant difference between EPC-RFID and barcodes is EPC-RFID can provide identification of assets (referred generally as products in supply chain domain) down to individual item level (e.g., two cans of soda would not be distinguished with the current barcode on each - the barcode now only identifies the class of product). This is due to the elasticity of the storage of a very large number on tag, allowing labeling of enormous ranges. Here we list some perceived benefits of RFID technology:

1. RFID technology does not require the line of sight as it does in the optical bar code system. This reduces labor cost, time and possibly storage space as required for barcode scanning.
2. RFID technology is inert to dirt, water damage and less prone to other damage as it happens to the bar code system. This reduces labor cost, material cost and time on repairing barcode labels.
3. RFID tags can be read in tens per second range. This is way higher than the optical barcode system. Time will be reduced and efficiency will be increased.
4. RFID tags can be read without human intervention and by following standards, can be read by any standard-compliant multi-frequency readers.
5. In a factory, RFID can be used to automate the inventory management system and manufacturing process like sorting.
6. In a supply chain, RFID enables a closer tracking of products from shipment to shop floor. By sharing the information, better coordination can be done.
7. In a retail shop, RFID offers the capability to do automatic check out, automatic shelf refill. This reduces customer complaints and their time on queuing.
8. RFID technology has the inherited capability to do Electronic Article Surveillance (EAS). Cost on managing a separate EAS system as in using barcodes will be eliminated
9. RFID can also be used for authentication and as a way to identify genuine articles. This can help to fight the counterfeit problem.
10. Due to the track-and-trace and authentication capability, RFID can help to fight gray market or parallel imports. It also helps to handle consumer returns or after sale support without receipts. This delivers better customer service and then, promoting brand loyalty
11. In conjunction with EPC, RFID offers the capability of real time tracking of products to the item level. This gives the supply chain a higher visibility on product movement and on product inventory. This helps to reduce the out-of-stock problem.
12. With the flexibility of writing company or product specific information onto the tag, RFID tags will serve as the pivot point where capabilities of future smart home appliances like smart washing machine, smart fridge will be leverage to the next level.
13. EPC-RFID is fully supported and backed by Department of Defense, big retailer chains like Wal-Mart in the US, Metro in Germany, Tesco in the UK and big manufacturers like Gillette and P&G.
14. RFID can be rolled out in different phrases and progressively according to the business needs without too many risks in dealing with coherence to current business processes and technical compatibility issues in the future. RFID can first be deployed at pallet level and proceed to the item level when tag price comes down. RFID does not mean to be a total replacement of barcodes overnight.
15. The apparel industry is a good candidate to take full benefit from using RFID technology due to its inherited advantage. Garment materials do not create problems for the RFID system as do in, for example, the soft-drink industry where water and metal complicate the propagation of electro-magnetic waves.