RFID for Beginners

24-January-2013
24-January-2013 15:08
in Technology
by Admin

What is RFID?

At the very simplest level, Radio Frequency Identification (RFID) technologies allow the transmission of a unique serial number wirelessly, using radio waves. An RFID system has two main components: the RF reader and the RF tag or label. When RFID tags are attached to physical objects they enable those objects to identify themselves to RFID readers through the use of radio frequency communication.

 

How does RFID work?

The basics of how RFID works is that Information is exchanged between RFID tags and a reader using radio waves. There are two types of RFID system passive and active which determine how the tag is powered. The most common system is passive which is where the tag is powered by an energy field transmitted by the RFID reader. The tag is “woken up” as it enters the energy and then transmits its data to the reader. In active systems, the tag is powered by its own battery and provides a more effective read range for the tag. The reader is commonly connected to a mobile device or computer either wired or wirelessly and will pass the tags information to the computer for further action.

 

RFID Tag

RFID tags come in all shapes and sizes but all of the tags share a common architecture comprising of an integrated circuit (IC), an antenna, housing and for active tags a battery. Tags are either active or passive which describes how the tag is powered both are equally important depending on the specifics of the application.

 

Frequency

RFID is fundamentally based on wireless communication, making use of radio waves, which form part of the electromagnetic spectrum (i.e. frequencies from 300kHz to 3GHz). It is not unlike two other wireless technologies, WiFi and Bluetooth. The three technologies are all designed for very different uses and therefore have different functionalities but there is shared ground between the three, with some hybrids starting to appear.

 

Band

LF

Low Frequency

HF

High Frequency

UHF

Ultra High Frequency

Microwave

Frequency

30-300kHz

3-30MHz

300MHz-3GHz

2-30GHz

 

Typical RFID Frequencies

125-134kHz

13.56 MHz

433 MHz

865 – 965 MHz

2.45 GHZ

 

2.45 GHZ

Approx Read Range

< 0.5 m

< 1.5m

0.5m – 5m

<10m

 

Typical data transfer rates

 

< 1kbit/s

~25 kbits/s

30 kbits/s

<100 kbits/s

Characteristics

Short-range,

low data

transfer rate.

Penetrates

water but not

metal.

Higher ranges,

reasonable data

rate (similar to

GSM phone).

Penetrates water

but not metal.

 

Long ranges, high

data transfer rate,

concurrent read of <100 items. Cannot penetrate water or metals.

 

Long range, high data transfer rate.

Cannot penetrate

water or metal.

Typical Use

Animal ID

Car

immobiliser

Smart Labels

Contact-less

travel cards

Access & Security

Specialist animal

tracking

Logistics

Moving

vehicle toll

 

Costs

It is important to understand that the cheapest tags readily available in the market will most likely have the following characteristics and functionality. The tag will need to be passive (manufacturing and component costs means active and semi-passive tags are unviable), with low memory (in the region of 64 bits - smaller memory means less silicon and therefore lower costs) and no re-write functionality.

 

There is a lot of information on the internet from companies claiming to supply tags at prices sub £0.10 but, unfortunately, this is in fact not the case. Many providers neglect to inform their potential customers of the volumes required to reach this pricing. In other cases, suppliers have been providing the chip and/or antenna only for this price which resulted in unusable tags until they have been mounted and sealed.

 

The average price for a tag of any frequency ranges from £0.30 to £0.50, depending on the type of tag and the volumes involved in the application.

 

There is scope to reduce this price slightly further by purchasing chips and antennas from alternative sources overseas but this brings in to question the overall reliability of the tag and therefore the solution. A tag that is only readable 50% will not provide the solution or the ROI required.

 

Therefore, whilst the industry has seen tag prices fall over the recent years, the price per tag is still the main obstacle to widespread adoption of RFID. However, the tags do not have to be sub £0.10 in order to derive a decent ROI for a solution.

 

Applications and the Future

The cost of the tags and the lack of standards have slowed the adoption of RFID into the market. The main adoption has been into “closed” applications, where often only a relatively small number of labels are required without the need for standards. For example, one supplier could supply all the tags and readers to track the movement of assets in a particular building – in this case, the payback is simply determined from a cost analysis. However, open systems – which hold the potential for billions and even trillions of tags yearly, are cost prohibitive so adoption into open systems has to date focused on high cost items. In recent years improvements to standards and the continued reduction in the cost of tags has allowed more open system applications to utilize RFID but there is still along way to go!

 

How to evaluate RFID for your business?

If your organisation is considering implementing RFID systems within your business then the best way to understand the true business benefits and the return on investment is to trial the solution within your environment. This approach will allow you to truly understand which technology or combination of technologies would best suit your application and process. Data Capture solutions work with a number of RFID technology partners to provide a proof of concept service which permits organizations to test and build a business case for RFID system.

 

Contact DCS for more details.

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