What is RFID?

“RFID is a powerful and versatile technology to identify, trace and manage a huge range of products, documents, animals and individuals, with no contact or direct visual field.”

The RFID systems are compounded by:

-reader with antenna
-transponder (tag, tag RF)
-computer or any type of mating controller

How does a RFID work?

It’s a technology of identification that uses radio frequency to transmit data. So it can be read without visual contact.

This communication needs a transponder or a RF Tag and a reader with an antenna, which can also be a writer. The writer can record new data in the chip of the transponder, when applicable.

When a Tag is nearby a reader, the field from the reader feeds the Tag and it transmits its data back to the reader and vice-versa, in case of a read/write tag.

What is a transponder or RF Tag??

It’s a combination of:

- Chip
- Antenna, that is connected to the chip
- and enclosure made by PVC, epoxy, etc.

The Chip is the principal item, because it controls communication with the reader. The Chips’ memory stores the data which is sent to the reader when the reader field activates it. There are read-only tags (RO) that have a single number, and read/write tags (RW), which can store data. The storage capacity is according to the kind of chip. In passive systems, the range of storage is between 64bits and 8kilobits.

The most recent chips have an anti-collision system, where it’s possible the read multiple transponders at the same time.

What is a Transponder reader?

It’s not much different from a bar code reader in terms of the function and computer connection. However, the transponder reader emits an electromagnetic field (radiofrequency) which feeds the transponder and it gives back the contents of its memory. The transponder reader can read a tag through plastic, wood, paper, concrete, glass, etc, unlike the laser reader (bar code), which needs direct contact.

What is a Transponder Writer?

It has the same characteristics of the reader, but it also writes data to the memory in a read/write tag.

When should I use the read/write tag (RW) or the read-only tag (RO)?

It depends on your demand. There are pros and cons as to whether to write information or not in the Tag.

It’s necessary to make an evaluation of your project to qualify the kind of tag you should use. There are advantages and disadvantages in centralizing your data in a single database with an on-line system (where the tag is a read-only) or decentralize it with an off-line system (where the tag is a read/write). Considerations such as “Do the specifications need to exist with the part for maintenance purposes?” or “Is the information easier to handle with a PLC or computer based system tracking and storing the information and issuing a bar code when the item is packed out?” The ability to Read or to Write gives us the flexibility to handle many varied applications in a manner that delivers the best Return on Investment.

What is the read range and why is it important?

The read range is a relevant factor for your system to work properly. It’s the max readable distance between the reader and the Tag. And it depends on the kind of tag (active or passive), range of the tag antenna, work frequency, reader power, etc. The read range should be optimized to each application.

How to choose the RFID system?

The environment of the application defines:

-frequency system
-kind of chip
-format and material of the enclosure (tag)
-kind of reader
-software
-network
-proximity to the part
-connectivity
-value of RFID vs. Bar Code

With this data, the system should be customized to your application.

What are the benefits of a RFID solution?

There are many, such as:

-a more secure system
-Decrease of operational costs
-No human mistakes
-Better satisfaction of the clients
-Increase the speed of the process, due to the automation
-better process quality control
-decrease of loss and inventories
-an environmentally tougher system
-a longer life system

Are there interferences in a wireless network made by a RFID system?

Not in most of the cases. It’s used in a different range of frequency, except the UHF systems. Even if there’s interference, it’s not worse than a wireless telephone interfering in a television. Even if both systems use the same frequency range, you should just avoid using the reader near the other disposal.

Are there any limitations to RF Tags in the identification of metal objects or products?

Metal can influence identification considerably. As we deal with magnetic fields, metal negatively interferes with the field. But, there are special enclosures to deal with this kind of limitation, so that we can identify automobiles, trains, containers, etc, within the read range.

Is the Smart Label really smart?

In comparison to smart cards, widely spread at the bank sector already, the smart labels are labels that have memory. Smart is something that has internal processing, or can make arithmetic calculations, or make decisions from information received. Smart labels are just labels with memory to store data and it would be more appropriate to say electronic or memory labels. But the term smart label has already caught on in the industry.

Is it true that a mini transponder (RF Tag) can protect people from kidnapping by locating them via satellite?

There are many hoaxes that chips were implanted inside people’s bodies and they can be tracked by satellite. Well, it’s not really possible. For someone to be detected by satellite he would need a GPS and it’s quite big and needs a long lasting battery. RFID and GPS are two separate worlds. A capsule with chips can be implanted in people and animals, but the read range is not more than 20 cm.