bloggingRFID
Thought leadership on embedded RFID and networked RFID from representatives of SkyeTek - the leader in embedded RFID

HF vs UHF: Choosing the Right Frequency

May 21, 2008 13:31 by jpeifer
With all of our customers, this is usually the first question that we need to address, “Should I use HF or UHF?” The easy answer is, of course, UHF allows for longer range, HF requires proximity. I read an article the other day about a vendor that believed this and tag price was all they really needed to know, and they are now starting to think they made the wrong choice.

In later posts we will go into more detail, but for now here is a quick overview of differences in tags and in readers. HF tags typically have a large user memory bank, memory on the tag that a user can use however they please. Certain HF tags also use secure communications protocols, protecting data as it moves between the reader and tag, and can provide anti-counterfeiting measures for high value products. But security and memory come at a price, literally, with some tags costing more than $1 per tag.

On the other end, UHF tags are almost the complete opposite. Smaller memory, usually only enough for an Electronic Product Code (EPC), no secure protocols, and long read range, all for much cheaper than HF tags. However, UHF tags with large user memory are starting to gain traction, and some tag manufacturers have started making inductive UHF tags, which have a more restricted range, but are extremely inexpensive. As a result, I wouldn’t be surprised to start seeing UHF gaining popularity in more markets.

But the story doesn’t end there. HF readers are much cheaper than UHF readers, NFC phones are becoming more popular, and contactless payment is becoming more pervasive (been to Best Buy lately?) all support for HF. So what does all this mean? In my opinion, it comes down to this: if you have many items to tag and few read points (like in a warehouse), UHF is a more logical choice, but if you have many read points in many places (such as cell phones) or you are tagging high value items, HF will be more beneficial. There are always exceptions, but this is a good start to making sure you don't end up with millions of the wrong type of tags.
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Of Frequency Wars and More Interesting Topics

April 22, 2008 12:46 by gwalter

Here are some insights from our Founder, Sean Loving from recent history: 

It appears as though some are taking sides in the RFID Frequency War. Most agree the *war* is between 900MHz UHF and 13.56MHz HF as the better solution for item level RFID tagging. Last month at the RFID World Conference in Dallas, Texas several people asked me "what frequency is going to win the war for item level tagging"? Then in just the past couple of weeks there have been several noteworthy op ed, articles and events that continue to explore this question.

There was that report from Odin about UHF versus HF for Pharma SCM and ePedigree. One important note is how the conclusions were based on their comparison of E-field UHF with H-field HF.

And there have been several other recent op eds and articles [pdf] that further explain some of the issues important to this *war*.

I think the discussion (thankfully) is starting to expand to include other factors that are equally as important as frequency. Namely, some of these articles and reports are starting to discuss "coupling".

Finally, the industry is starting to understand that coupling, the wireless but physical connection between tag and reader, is independent of frequency.Coupling is something the industry is only starting to recognize as a key RFID systems level consideration. Here are a few terms to keep straight for these two basic types of coupling:

Electric field coupling, E-Field, Capacitive Coupling, Far-Field, Dipole antenna, Magnetic field coupling, H-Field, Inductive Coupling, Near-Field, Loop antenna

As a long time technical expert, I started SkyeTek already with several years experience making E-field tags and readers at both LF and HF – I think before Matrics and Alien were sampling their first UHF tag silicon.Now there appears to be a reverse opportunity for making inductive coupling tags with UHF tag silicon.The promise is to solve some remaining problems with UHF item level tagging, and to further drive the economy of scale for Gen2.

Indeed, SkyeTek applauds some of the new tag product announcements and the flurry of reader, antenna, and installation development that will necessarily follow to provide among other things - UHF item level tagging.

The result is that more products, systems and applications than ever will become RFID-enabled.

Until now the industry has focused more on the differences than the similarities between HF and UHF.Now that's starting to change as awareness continues to grow. SkyeTek is a neutral party because we provide Tagnostic(R) HF and UHF RFID reader technologies that easily configure for use with either type of coupling. Because we don't prefer either frequency HF or UHF, we can provide the best solution for our customers, instead of looking to force our solution on the world.

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