RFID Systems - Frequently Asked RFID Questions

Feb. 17, 2012 - PRLog -- What is Automatic Identification?
Automatic identification, or auto ID for short, is the broad term given to a host of technologies that are used to help machines identify objects.  Auto identification is often coupled with automatic data capture. That is, companies want to identify items, capture information about them and somehow get the data into a computer without having employees type it in.  The aim  of most auto-ID systems is to increase efficiency, reduce data entry errors, and free up staff to perform more value-added functions, such as providing customer service.  There are a host of technologies that fall under the auto-ID umbrella. These include bar codes, smart codes, smart cards, voice recognition, some biometric technologies (retinal scans, for instance), optical character recognition and radio frequency identification (RFID).

How does RFID system work?
An RFID system consists of a tag, which is made up of a microchip with an antenna, and an interrogator or reader with an antenna. The reader sends out electromagnetic waves.  The tag antenna is tuned to receive these waves.  A passive RFID tag draws power from a field created by the reader and uses it to power the microchips circuits.  The chip then modulates the waves that the tag sends back to the reader. The reader converts the new waves into digital data.

Are there any health risks associated with RFID and radio waves?
RFID uses the low-end of the electromagnetic spectrum.  The waves coming from readers are no more dangerous than the waves coming to your car radio.

What is an Electronic Product Code?
The Electronic Product Code, or RFID, was developed by the Auto-ID center as a successor to the bar code.  It is a numbering scheme that will be used to identify products as they move through the global supply chain.

Why is RFID better than using bar codes?
RFID is not necessarily "better" than bar codes.  The two are different technologies and have different applications, which sometimes overlap.  The big difference between the two is bar codes are line- of -sight technology.  That is, a scanner has to "see " the bar code and read it, which means people usually have to orient the bar code towards a scanner for it to be read.  Radio frequency identification, by contrast, doesn't require line of sight.  RFID tags can be read as long as they are within range of a reader.  Bar codes have other shortcomings as well.  If a label is ripped, soiled or falls off, there is no way to scan the item.  The bar code on one milk carton is the same as every other, making it impossible to identify which one might pass its expiration date first.

Will RFID replace bar codes?
Probably not.  Bar codes are inexpensive and effective for certain tasks. It is likely that RFID and bar codes will coexist for many years.

Is RFID New?
RFID is a proven technology that's been around since at least 1970s. Up to now, it's been too expensive and too limited to be practical for many commercial applications. But if tags can be made cheaply enough, they can solve many of the problems associated with bar codes.  Radio waves travel through most non-metallic materials, so they can be embedded in packaging or encased in protective plastic for weather-proofing and greater durability.  And tags have microchips that can store a unique serial number for every product manufactured around the world.

If RFID has been around so long and is so great, why aren't all companies using it?
Many companies have invested in RFID systems to get the advantages they offer.  These investments are usually made in closed-loop systems - that is, when a company is tracking goods that never leave its own control. That's because all existing RFID systems use proprietary technology, which means that if company A puts an RFID tag on a product, it can't be read by Company B unless they both use the same RFID from the same vendor.  But most companies don't have closed-loop systems, and many of the benefits of tracking items come from tracking them as they move from one company to another and even on country to another.

Is the lack of standards the only thing that has prevented RFID from being more widely used?
Another problem is cost. RFID readers typically cost $1,000 or more. Companies would need thousands of readers to cover all their factories, warehouses and stores.  RFID tags are also fairly expensive - 20 cents or more - which makes them impractical for identifying millions of items that cost only a few dollars.

What is the difference between low, high and ultra-high frequencies?
Just as your radio tunes in to different frequencies to hear different channels, RFID tags and readers have to be tuned to the same frequency to communicate.  RFID systems use many different frequencies, but generally the most common are low - (around 125KHz), high - (13.56 MHz) and ultra-high frequency, or UHF (850-900 MHz). Microwave (2.sigh) is also used in some applications.  Radio waves behave differently at different frequencies, so you have to choose the right frequency for the right application.

How do I know which frequency is right for my application?
Different frequencies have different characteristics that make them more useful for different applications.  For instance, low-frequency tags are cheaper than ultra high frequency (UHF) tags, use less power and are better able to penetrate non-metallic substances.  They are ideal for scanning objects with high-water content, such as fruit, at close range.  UHF frequencies typically offer better range and can transfer data faster.  However, they use more power and are less likely to pass through materials.  Because they tend to be more "directed", they require a clear path between the tag and reader.  UHF tags might be better for scanning boxes of goods as they pass through a bay door into a warehouse.  It is probably best to work with a consultant, integrator or vendor that Can help you choose the right frequency for your application.

Do all countries use the same low - high and ultra-high frequencies?
Most countries have assigned the 125 KHz or 134 KHz area of the radio spectrum for low -frequency systems, and 13.56 MHz is used around the world for high-frequency systems. UHF RFID systems have only been around since the mid-S and countries have not agreed on a single area of the UHF spectrum for RFID. Europe uses 868 MHz for UHF the U.S, uses 915 MHz. Until recently, Japan did not allow any use of the UHF spectrum for RFID, but it is looking to open up the 960 MHz area for RFID.  Many other devices use the UHF spectrum, so it will take years for all governments to agree on a single UHF band for RFID.  Governments also regulate the power of the readers to limit interference with other devices.  Some groups, such as the Global Commerce Initiative, are trying to encourage governments to agree on frequencies and output.  Tag and reader makers are also trying to develop systems that can work at more than one frequency, to get around the problem.

I've heard that RFID doesn't work around metal and water. Does that mean I can't use it to track cans or liquid products?
No. Radio waves bounce off metal and are absorbed by water at ultra-high frequencies.  That makes tracking metal products or those with high water content problematic, but good system design and engineering can overcome this shortcoming.  Low - and high - frequency tags work better on products with water and metal.  In fact, there are applications in which low-frequency RFID tags are actually embedded in metal auto parts to track them.

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Texpak, Inc. is one of the world's leading suppliers of product identification, packaging specialties, bar coding software, tags and labels.