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How Does RFID Technology Work?

Gavin Phillips 31-05-2017

What’s in your wallet? That famous credit-card company tagline takes a more serious meaning these days. Credit and debit cards with an embedded Radio-Frequency Identification (RFID) tag are now the norm Why You Should Protect Your Waveable Visa Card From Mobile Fraudsters Read More .


This is one place you use RFID. But there are plenty more places you use RFID technology, probably without even realizing. The RFID market was worth over $10 billion in 2015, forcast to rise to over $13 billion in 2020.

So, what is RFID?

What Is RFID?

Radio-Frequency Identification is the use of radio waves to read, capture, and interact with information stored on a tag. Tags are usually attached to objects, and can be read from several feet away. Furthermore, the tag doesn’t always have to be in the direct line-of-sight to initiate interaction.

An RFID tag is an easy way to assign a unique identity to an object. Additionally, they do not need an internal power source, while a tag can be as small as a grain of black pepper. Meaning they are easily embedded almost anywhere — hence their popularity.

How Does RFID Work?

A basic RFID system comprises two parts: the tag, and the reader.



The RFID tag has an embedded transmitter and receiver. The actual RFID component contained in a tag has two parts: an integrated circuit for storing and processing information, and an antenna to receive and transmit a signal. The RFID tag has non-volatile memory storage, and can included either fixed or programmable logic for processing transmission and sensor data.

How Does RFID Technology Work? RFID Tag

Tags can be passive, active, or battery-assistive passive.

A passive tag is the cheapest option, and features no battery. The tag uses radio energy transmitted by the reader.


An active tag features an onboard battery, periodically transmitting its credentials.

A battery-assistive passive tag also features a small onboard battery, but is only activated when in the presence of an RFID reader.

Furthermore, a tag may be either read-only, or read/write. A read-only tag has a factory assigned serial number used for identification in a database, while a read/write tag can have specific custom data written to the tag by the user.


The RFID reader features a two-way radio transmitted-reciever (transciever), sometimes referred to as an interrogator. The transceiver transmits an encoded radio signal to interogate the tag. The radio signal essentially wakes or activates the tag. In turn, the tag transponder converts the radio signal into usable power, and responds to the reader.


How Does RFID Technology Work? rfid transponder1

Types of RFID System

We generally classify the type of RFID system by the type of tag and reader. There are three common combinations:

  • Passive Reader Active Tag (PRAT): The reader is passive, only receiving radio signals from an active tag. Because the tag is battery powered, the transmit/reception range can be from 0-2,000 feet (0-600m). As such, PRAT is a flexible RFID solution.
  • Active Reader Passive Tag (ARPT): The reader is active, transmitting an interrogator radio signal, receiving authentication signal replies from passive tags.
  • Active Reader Active Tag (ARAT): The reader is active, and interacts with active or battery-assistive passive tags.

In addition to the RFID system type, RFID uses a set of regulated frequency bands. See the frequency band table below for an understanding of certain frequencies and their uses.

How Does RFID Technology Work? RFID Frequency Bands
Image Credit:


What is OPID?

Optical RFID (OPID) is an RFID alternative that uses optical readers. OPID operates in the electromagnetic spectrum between the frequencies of 333 THz and 380 THz.

How Much Data?

The amount of information stored on an RFID tag varies. For instance, a passive tag may only store up to 1024 bytes of information — that’s just one kilobyte (KB). Laughable in terms of modern storage capacity, but enough to store a full name, identification number, birthday, SSN, credit card information, and so much more. The aerospace industry, however, use passive ultra-high frequency RFID tags with 8KB storage to track part history over time. These could store a massive amount of personal data on.

Common RFID Uses

RFID tags are everywhere. Because they’re easily attached to almost anything, have no power requirement, and are potentially minute, they are used in all walks of life, including:

  • Goods management and tracking
  • Person and animal tracking
  • Contactless payments
  • Travel documents
  • Barcodes and security tags
  • Healthcare data management
  • Timing

RFID is also making waves in the ever-growing smart home market. (Check out Ian Buckley’s tutorial on making a smart lock using an Arduino and RFID DIY Smart Lock with Arduino and RFID Here's how to build a simple RFID-based smart lock using an Arduino as the backbone and a few cheap components. Read More ). In 2010, the cost of RFID significantly decreased. At the same time, RFID reliability increased due to global drive in RFID standards. Suddenly, an extremely reliable but cost-effective tracking or identifcation system was available.


The sudden surge in RFID has created security issues, too. Most recently, the advent of contactless payment cards featuring an RFID tag has come under scrutiny. Nefarious individuals were “skimming” payments Trust the Tinfoil: 5 Ways to Protect Against Remote Radio and RFID Hacks RFID chips are everywhere, from in-store tags to smartphones. As cheap RFID enabled products continue to proliferate you need to know the best ways to protect yourself from the criminals. Read More from contactless cards using portable payment terminals, all while the RFID-enabled card resides in the targets pocket or wallet. If you’re worried about this type of fraud, check out Joel Lee’s run-down on RFID blocking wallets What Is an RFID-Blocking Wallet? (And Which Should You Buy?) If you have cards, passports, or devices with RFID chips, then an RFID-blocking wallet could be important for keeping your data safe. Read More .

18 RFID Blocking Sleeves (14 Credit Card Holders & 4 Passport Protectors) Ultimate Premium Identity Theft Protection Sleeve Set for Men & Women. Smart Slim Design Perfectly fits Wallet/Purse 18 RFID Blocking Sleeves (14 Credit Card Holders & 4 Passport Protectors) Ultimate Premium Identity Theft Protection Sleeve Set for Men & Women. Smart Slim Design Perfectly fits Wallet/Purse Buy Now On Amazon $9.99

How Does RFID Technology Work? rfid blocking wallet credit cards

In the U.K., another example involves RFID tags stored in passports. When first introduced, the encryption on the new U.K. passport was cracked within 48 hours. Additionally, reports emerged that criminals were stealing post containing a new passport, scanning the RFID tag for the data 5 Myths About RFID Chips and Why You Shouldn't Worry RFID chips are often equated with myths of global tracking and apocalyptic end-of-the-world scenarios, but the truth is far more mundane than you might think. Read More , and then sending them on their way.

RFID is Here to Stay

RFID is an enormous industry. We use it almost everyday. The package that arrived at your house, the card you paid for your lunch, your door-opening smart home hand-implant, and more, all use RFID.

And as it RFID evolves, so will its uses — exciting times!

What do you use RFID for? Do you use it in your smart home setup? Have you bought an RFID blocking wallet? Let us know your RFID tricks and tips in the comments below!

Related topics: RFID, Smart Sensor.

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  1. Stephen Fannon
    November 15, 2017 at 5:39 pm

    I recently became aware of 3 fraudulent transactions on my bank current account.
    Upon investigation I was declined a refund because the bank had identified that the transactions had been carried out using my iphone and debit card details. Because I had not lost my phone or my card the inference is that I have either been negligent or worse, dishonest.
    I can confirm that at no time time has any one else had access to my mobile and at no time has it been misplaced.
    Could this technology and the resultant skimming activity apply here?


  2. Safwan Shaikh
    August 4, 2017 at 8:42 pm

    Currently i am working as a Rfid engineer working on projects such as container tracking. I deal with both Reader and tag as im familiar with this technology its good and effective.

  3. mike
    April 22, 2017 at 2:00 am

    I hate bar codes and for that matter RFID chipping.
    Have you ever tried to get a bar code strip off of a banana or any other fruit?
    When you think about it, most of this high tech marking isn't for our good, its for some corporation so it can save a few cents on inventory and labor costs.

    Wonder where all those jobs are going?

    Well, the more automation we get as in bar codes etc.; the less people are needed. All you need is a code reader/RFID reader strapped to the conveyor belt and presto-change-o, one less job. Not everyone can or wants to become a chair potato slamming out code. Next time you can't find a competent mechanic, carpenter or other tradesman remember to thank your RFID chip.

  4. Jim
    November 2, 2016 at 12:33 pm

    RFID is an initialization of – Radio Frequency Identification Tag is not correct
    RFID is an initialization of – Radio Frequency IDentification

    • Philip Boepple
      August 10, 2017 at 4:55 pm

      I thought it was more to the effect of "Radio Frequency Identification Device" but I could be wrong. Thank you. Phil

  5. Wes
    May 6, 2016 at 9:56 pm

    Government paranoia! Is there no end to it. You're probably in more danger from your next door neighbor than big-brother government. We elect or government leaders. Who decides whether or not your next door neighbor is a danger?

    • Guy McDowell
      May 20, 2016 at 7:47 pm

      What if your next-door neighbour is in the government???
      Very few individuals are likely to be in danger from gov't activities like this. It's what a gov't does to a population that is dangerous. Maybe not physically, or immediately obviously, but the erosion of rights is real and does happen.

  6. Patrick Sweeney
    September 28, 2009 at 8:31 am

    RFID (pronounced correctly "ARE-F-I-D") is one of the most transformational business technologies of the century. It is saving lives and saving businesses billions of dollars because humans are no longer needed to count and record data on everything from airplane parts to jeans.

    RFID systems are making our world safer by preventing counterfeit parts from going into airplane repair facilities (MRO) or keeping surgical sponges from being mistakenly left inside a patient.

    The Hitachi Mu chips referenced, like all passive RFID tags, are bound by the laws of physics and the inverse square law of RF propagation. Essentially the smaller the tag the smaller the read range. The Mu chip has a read range of under a centimeter.

    Don't fall for Hollywood conspiracy theories, a passive UHF tag can not be inhaled, injected or implanted and read outside the body at great distances. It's simply impossible. Worry more about the phone company's GPS capability in your mobile phone and their data mining of your behavior.

    • Guy McDowell
      September 28, 2009 at 7:19 pm

      I'd say you had a vested interest in promoting them so much. However, whether these things can be inhaled or not is not the point. The point is that they are not the panacea that a lot of people think they are.

      As you said, they save companies money by not having to have people to do inventory. Is that a good thing or a bad thing? Depends which side of the coin you are on.

      Could they be used for nefarious purposes? Of course they can - all things can.

      How great a distance is a great distance? How close does the offender need to be to get the data? As seen in the video, proximity isn't an issue. How about the doorways that are set up to scan RFID tags as a person takes tagged items through? Could that not be used to scan tags in personal items as a person is entering, say, a sporting event?

      It's not one technology in particular to consider - there are so many that make it easier for someone to be invasive in your life. These same technologies can all be very beneficial as well, and I urge everyone to consider both sides before drinking the marketing Kool-Aid.

    • Philip Boepple
      August 10, 2017 at 5:01 pm

      Very good point there. I too, have been concerned about the use of "smart phones" and so forth. After all, many of those can be used to track someone's current location, sort of like with a GPS device. Never the less, that can be very desirable if you are dialing 911 while stranded way out in the middle of no where and are lost or something, as long as you are in the service range! Yes, today's late technological advances are like elevators, they have their ups and downs.

  7. Charles
    September 27, 2009 at 11:26 am

    Great article! What alarms me the most about things like the RFID chip, H1N1 vaccine and other "tin hat" theories is how easily they can be implemented by a simple govt. regulation and there's not much we can do about it.

    • Philip Boepple
      August 10, 2017 at 5:05 pm

      The "government regulation" part is what I myself am most afraid of. Likely though, if enough of us stay active about it and raise a little scrutiny over government involvement and hold our politicians accountable, we may well hinder the bad stuff from coming around.