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Introduction to Retail RFID Technology, part 2 - Radio technology and radio waves

This is the second part of the article series Introduction to RFID technology, the basics of RFID explained by the Tech Geek.

The aim of this series is to dive into the House of RFID archives and to present some of our earlier researches. The first article, Introduction to Retail RFID Technology, part 1 discussed RFID in general. This time we take a look at radio technology and radio waves as they are an important element in RFID technology.

RFID is based on radio technology. This means that the information is transferred through radio waves. In his book "RFID Implementation", Dennis E. Brown (2007) describes a radio wave accordingly:  

"A wave is a disturbance that carries energy from one place to another. Radio waves are created when electrons are passed through a conductor, like an electrical wire. The current creates a magnetic field. Fluctuations in the current produce changes in the magnetic field, creating waves of electromagnetic energy. These are called electromagnetic waves".

Radio waves, more specifically, are low-frequency electromagnetic waves. They oscillate more slowly, and their wave lengths are longer than of other types of electromagnetic waves. Oscillation refers to the waves repeatedly rising in the intensity to a peak, fading a minimum, and then rising to their peak level again. The complete path from one peak to the next one forms a cycle, which refers to the oscillation rate of the wave: the number of cycles that happen in the time of one second. (Brown 2007)

RFID technology operates mostly on four different frequency levels: low frequency (LF), high frequency (HF), ultra-high frequency (UHF) and microwave (MF). Besides the operating frequencies, the most crucial difference between the frequencies is the maximum reading distance. The higher the operating frequencies, the longer the maximum reading distance. Roughly, on LF the reading distance is a few centimeters and on UHF several meters. The table below presents the frequencies and some of their application areas.

Readingdistances2

LF technology

LF technology operates between 30kHz and 300kHz. LF is typically used in animal tracking: domestic animals and pets carry their own RFID tags enabling to identifying them if needed. Also the majority of bus cards nowadays have an LF RFID tag: the floods of passengers move smoothly when each passenger's trip is registered with a simple sweep of a card. LF technology is also used in access control: the more users a school, a company premises or an institution has, the more probable it is that the people entering the premises must have their own RFID tag equipped "key". With these kinds of solutions each individual person entering the premises can be tracked, and if something gets stolen or damaged, the last people entering the specific area can be identified. Car immobilizers are also one use area: nowadays stealing a car by starting it "from wires" is quite challenging since the newer cars will not start up the engine unless the proper key is inserted. Also, one of the rising application areas of LF is the NFC technology. It has been acting as a remarkable tool in enhancing customer experience.

HF technology

HF operates between 3MHz and 30MHz. Libraries and archives use RFID readers operating on this frequency. HF tagging is used also in laundries and in shipping parcels. And last but not least: airports put HF RFID tags on luggage in order to improve the luggage handling, enhance faster operations in re-routing and generally make sure that a bag is in the same airplane as the right passenger. Simply, the HF application area is roughly the same as in the LF technology with some exceptions, such as animal tagging is only for LF technology.

A common application for HF is NFC (Near Field Communication). The NFC allows smartphones and other enabled devices to communicate with other devices, which contain an NFC tag. NFC can be used for example in paying at the cash register, or reading product information. Also opening a door lock via NFC is possible.

Shutterstock _126187775_NFC_web

UHF technology

UHF operating frequencies are between 300 MHz and 3 GHz, and most of the new commercial applications have been created on UHF. These consist of retail applications, asset management and supply chain logistics, for instance.

EPCGlobal has created the standards around the frequencies. Already 78 countries (96,5% of the global gross domestic product (GDP)) have regulations in place or will be in place shortly.  In 3 countries (1% of the global (GDP)) regulations are in process, and in 43 countries (2,5% of the global (GDP)) information is not yet available.

What is worth noting is the fact that all the countries and continents do not use the same UHF frequency ranges. Therefore, when moving from one continent to another the differences in the frequency ranges are so remarkable that necessarily the same devices are not able to operate on different continents. Therefore, it is important to inform the manufacturer of readers about the continent (or country) where the devices are used in future.

In our next article, the Tech Geek discusses different types of tags. Stay tuned for part 3!

References

Brown, Dennis E. (2007) RFID Implementation. McGraw-Hill Communications.

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