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Jul 07, 2017

The Evolution of RAIN RFID Testing Started with Inlays, and Ends with…

中文版 Chinese version

Evolution of organisms is one broadly accepted theory. Let me walk you through the phases evolution has taken when it comes to RAIN RFID tag testing.

Starting Point: The RFID Inlay

In the end of 90s there were no off-the-shelf solutions to start doing RFID research and tag testing. Hence the classical Radar Cross-section (RCS) seemed like a great way to characterize the UHF antenna of an inlay. It’s just that such a passive antenna test didn’t enable designers even to optimize the forward link: matching the impedance of IC with the impedance of the antenna. As a result, it was a struggle to get the tag tuning right. Additionally, the RCS measurement told nothing of the read range that the inlay design can deliver.

Delta Radar Cross-section (deltaRCS) was a serious step in the right direction for two reasons: the impedance match could be better analyzed and the fundamental reverse link parameters were brought into consideration. Read ranges started to improve. Around 2005-2007 also the first commercial tag test systems became available. Those systems, such as the Tag Analyzer from SAVR Communications, the Voyantic Tagformance and MeETS from CISC, already utilized the Class 1 Gen2 protocol to better grasp the actual performance of an RFID inlay. Pavel Nikitin’s paper from 2012 explains the theory and practicalities of diverse test systems in detail.

As tag prototypes were made and production samples tested, many companies focused mainly on the inlay performance in free air conditions. It didn’t take long for the first experts to realize that the test results better correlated with the real-world use case performance when the inlays were attached on various materials prior to testing. So, approaching the current decade it seemed half of the industry was busy working with various reference material sets, and the other half with aluminum plates of various sizes.

Era of Testing Tags on Items

To bring more sense into real-world performance of inlays, Voyantic introduced the Application Development Suite already in 2008. With the Population Analysis function anyone could visualize and study the behaviour and properties of tags in groups. As we have later learned, very few did such analysis before 2011, which manifests two related findings:

  1. The more groundbreaking the concept, the longer time it takes to really sink in
  2. It takes a lengthy period of time for engineers to learn how to explain certain groundbreaking concepts in an understandable way.

Tag-to-tag close coupling effects are indeed complex, and only partially understood and explained by the academic community even today. As a kind of workaround, the ARC Program emerged in 2011 to combine exhaustive label testing with data collection from actual RAIN use cases in retail. Outcome of that analysis are the ARC performance categories and the related certified inlay lists.

These ARC inlay lists simplified tag selection for the US retailers. I’d also state that the success of the ARC program pushed the technology vendors to seek additional ways to ease the adoption of RAIN RFID technology by collaboration. It can be said that the Program may have slowed down the market entry time for new inlay types and vendors obviously because they needed to pay and wait for certification tests before getting on those lists.

On the positive side waiting pays off, because the ARC inlays lists are one functional way for a new vendor to gain access to the US retail deployments.

Early this decade the performance testing elsewhere in the RFID ecosystem already focused on tags on actual items. However, the industry lacked a documented and open framework to correlate various test setups with each other. This void, together with the industry’s quest to improve the scalability of deployments, led to VILRI’s tagged item prototype project. Eventually that project gave birth to the Tagged Item Performance Protocol, aka TIPP, in 2015.

TIPP is a standard-like guideline from GS1 that establishes and combines three fundamental aspects:

  • Key performance metrics for RAIN enabled items
  • Test methodology that anyone can repeatedly use to extract these metrics
  • Performance grades for individual and stacked items.

Among its other benefits, the open and thoroughly documented TIPP guideline enables anyone to easily communicate their tagging requirements without sharing details of their processes and use cases.

Following the TIPP approach tagging solution providers are free to innovate and offer their latest products and solutions immediately without the need to have them certified by third parties.

How Would You Like Your RAIN Enabled Items? Separate, Boxed, Stacked, Hanging…

Close coupled RAIN enabled sporting goods

In the fall of 2017 an update to TIPP introduces a new test protocol for dense hanging stacks. This test protocol puts 100% reads of all the items to the focus, and thus leaves the close coupling effect purely for tagging experts to handle and solve. I anticipate that RAIN deployments especially around sporting goods retail will benefit from this new test protocol.

RAIN Read Performance Requires Input Also From the Reader Side

Albeit the tag side already enjoys highly sophisticated performance test framework, there are still a few missing pieces on the RAIN reader side. The Reader Sensitivity Test Recommendation from the RAIN Alliance was a grand milestone already. The dialogue and evolution would greatly speed up if the industry stakeholders, such as GS1 and RAIN Alliance, would take initiative to derive meaningful open performance metrics for read zones and readers in general.

That’s my evolution story for now. And no, the evolution of RAIN tag testing has not stalled, instead it’s constantly looking for new paths to make RAIN technology spread more efficiently. That’s also where Voyantic keeps on investing in. Your feedback on these thoughts will be greatly appreciated!

Jul 08, 2016

Downgrading Your Spec Does Not Make a Quality Tag – Thoughts About RFID Quality

中文版 Chinese version

I work as the CEO of Voyantic, a company that specializes in RFID test and measurement equipment. Since our systems are used by hundreds of companies around the world, we often come across cases where a customer needs our help to verify that their tags work as they should. This is a story about a case where things went wrong.

Tagging Athletes in Cross-country Skiing

We got involved with a very interesting case a couple of years ago. A small RFID integrator that we have known for some time wanted to tag athletes in a cross-country skiing competition. The idea was to use RFID for timing the race. And you can guess that if someone spends several hours on the ski track, being left without a race time is definitely not an option.

Cross-country skiing is a healthy hobby and also a good application for RFID timing – Photo by Sorbis / Shutterstock.com

There are many different ways to tag athletes in timing solutions. Common approaches in running competitions include integrating the RFID tags to the race bibs or attaching them to the shoes of the runners. However, in this case, the chosen approach was to buy wrist-band tags and to attach them to the ankles of the skiers. The tags were read by fixed readers that were set up on the side of the tracks.

The integrator went through the specifications of several different wrist-band tags and finally contacted a fairly well known maker of specialty tags for some samples. The samples arrived the following week, and the integrator ran some field tests. Everything worked well. He was able to detect every skier that passed the reader antenna.

So the integrator decided to order the tags that he needed for his application. Once again, there was a timely delivery of correct amount of tags. However, when he started to build the application, he noticed that not all of the tags were working. A typical discussion between an unsatisfied customer and a worried supplier followed.

The conclusion was that all the supplied tags worked according to the specification.

The tag manufacturer tested both working and non-working tags attached to the wrist of whoever they considered to be their standard-human. All tags were readable from a distance of 2 m which was the specification. But they didn’t all work in the end application. How is this possible?

Analysis

We got involved with the case at this point. We were asked to take a look at the tag samples to try to understand what was going on. So we ran a performance test for the tags using the Tagformance measurement system. The results from the Threshold Sweep measurement are shown below.

Performance variations of wrist-band UHF RFID tags measured with the Tagformance system

We tested the tags in free air, so they were not attached to a wrist or an ankle. But even in this setup it is clearly visible that there are significant variations in the tuning and performance of the tags. So this is what we think happened:

  1. The integrator decided to use the tags differently from what the manufacturer had specified
  2. The first samples sent by the tag manufacturer performed clearly above the spec
  3. The integrator concluded that this tag will work in the application
  4. The next tag batch – even though still within the original spec – performed differently
  5. A part of the tags didn’t work.

So, it is very hard to point fingers in this case. But there is something that the RFID industry needs to improve in. The industry is already doing a decent job in reporting the performance of their tags, e.g. in expected read range. But I think there is a lot to improve in how performance variations are reported, because that is a key factor in building reliable RFID systems.

And what happened with the skiing competition? Did the integrator get the system to work? He did. But he had to manually test through the tags and hand-pick the ones that worked well enough. Hardly a perfect outcome but every skier got their time.

My company Voyantic specializes in test and measurement solutions for the RFID industry. Are you interested to learn more about RFID quality control? Download our sample quality test report and contact us.

Download the Sample Quality Test Report!

See what performance testing can tell you about a tag – and how this data can be used to improve your production quality

Feb 12, 2016

What Gen2v2 Security Offers for RAIN RFID Applications

中文版 Chinese version

In October 2013, the management board of GS1 ratified text: EPC Gen2v2. These new features ease the adoption of RFID especially in application areas where the tag carries more information than only its identification. Let’s have a more detailed look at one new key feature of Gen2v2: authentication.

What Does Authentication Mean?

So first of all, what is authentication? A quick Google search resulted with the following definition:

Authentication is the process of determining whether someone or something is, in fact, who or what it is declared to be.

In the RAIN RFID (UHF RFID) context, that something can be either a tag or a reader. In tag authentication, a reader asks a tag to encrypt a message using its stored secret key. If the reader is able to decrypt the tag response, the tag is genuine. This approach can be used to detect counterfeit tags, and as a result counterfeit items. Similarly, in reader authentication, access to a tag is limited to authentic readers. This approach can be used for example in electronic payment solutions. Ken Traub of Ken Traub Consulting wrote a very down-to-earth post about this topic.

Test setup for automatic vehicle identification

RAIN RFID tags that implement cryptographic security are expected to be more expensive than the simplest retail labels. As a result, they will only be used in application areas where authentication gives a significant advantage. Such fields include at least

  • Electronic road tolling
  • Vehicle registration
  • Access control
  • Asset tracking and brand protection
  • Parking and vehicle authentication

The First Secure Tags and Readers Already Available

In Spring 2015, NXP released the first Gen2v2 tag IC that provides cryptographic authentication, the UCODE DNA. Several tag manufacturers are already providing tags with this IC. On the reader side, upgrading to Gen2v2 requires a firmware update, and at least Nordic ID already has added Gen2v2 support to their readers. So, the technology is available and there seem to be several ongoing pilots that use Gen2v2.

Different Crypto Suites

Gen2v2 is not concerned with which authentication method is used. Instead, the different crypto suites are defined under the ISO/IEC 29167 standard family. For example, NXP UCODE DNA uses the AES (Advanced Encryption Standard, ISO/IEC 29167-10) crypto suite. Some crypto suites may be optimized for low power consumption and quick authentication, whereas others may provide more secure authentication. As new Gen2v2 tags appear to the market, we will most likely also see different approaches to authentication.

What Does Security Mean for RFID Testing?

Since Gen2v2 is backwards compatible with Gen2, all Gen2 test methods apply just as well to tags supporting the new standard. The most widely used performance test method for characterizing a tag is measuring its sensitivity as a function of frequency. This reveals both the tuning of the tag as well as the operating range that can be acquired. Typically, the same amount of power is required to identify a tag and to read its memory contents. However, writing to the tag usually takes more power, thus yielding to a shorter write range.

Voyantic Tagformance Pro RFID measurement system

The Gen2v2 security functions introduce a new sensitivity level. The tag’s crypto engine that is required for the authentication may need more power than simply identifying the tag. The figure below shows the sensitivity of a Smartrac Dogbone with the NXP UCODE DNA IC. As the figure shows, authentication needs more power than just identifying a tag, however the difference is only 1 to 2 dB whereas writing the tag memory requires significantly more power.

Sensitivity of a Smatrac Dogbone with NXP UCODE DNA IC

My company Voyantic delivers test and measurement systems for companies that either develop or use Gen2v2 tags. The Voyantic systems enable companies to reach excellence in tag design and to find the most suitable tag for each application.

If you are interested to learn more, please contact us and let’s talk more!

Dec 11, 2015

This Doesn’t Look Right – Should I Contact Technical Support?

What do you do if, one morning, a new light with some strange symbol is suddenly lit on your car’s dashboard? You probably pull over and start browsing the car owner manual. You may be a little worried. Did I do something wrong? Can I fix this myself, or does the car need to be serviced? How long will I need to survive without my car?
In the same way, your Tagformance, the RFID test system that you typically use every day may have a problem you need to solve. You may already be an experienced user, or maybe you have just recently started to work with the system. When a new error message pops up or you get unexpected measurement results, it’s just like with your car. What’s wrong? Should I contact Voyantic Technical Support?

The answer to the last question is yes. You should.

*‘No such thing as a stupid question’ is a common phrase with a long history, and it makes perfect sense to me. *

If you have a problem with anything, and there is a possibility to get it solved quickly by asking someone who can help you, why shouldn’t you? The one who asks the “stupid question” may be doing a service to everyone, including the vendor, by pointing out a visible improvement to the product.

Here are some more or less typical situations where you might wonder if you should contact the vendor or just carry on. Uncertainty: You are performing measurements that look nice and smooth, but deep down, you are still wondering whether the results are correct? Is there some bias in the device? Am I measuring the right way? By contacting Voyantic Technical Support, we can verify if the device is OK by comparing the reference tag measurement results with the same measurement setup. We can also measure your sample tags and give a second opinion of the results and maybe give pointers on what else you can measure from your tags.

Differences between sites: You may have a colleague in the next room or on the other side of the globe doing the same measurements that you are. The equipment may be the same, the setup may be identical, but still, your results don’t match completely. For example, you get a theoretical read range value of 11 meters, and your colleague measures 10 meters. One meter sounds like a lot, but is it after all? By looking at the measurement data, we can verify whether the difference is something to worry about, or if it fits into production variation and typical measurement accuracy. Other factors, such as temperature, may cause a difference. The effect of temperature is described in more detail in an Application Note, which can be downloaded here. While visiting the site, you may find other Application Notes worth reading too.

Missing features: Different Tagformance measurement options are enabled with the license file. We can create license files where any measurement option can be enabled for a given time. So, if you think that one or more options could be useful for your work, we can enable the option for a trial period. To name a few;

  • Scripter is a great tool to automate your daily measurement routines and reduce the human error from the results.
  • The Tagformance has two Application Programming Interfaces, APIs, that enable you to write your software that uses the Tagformance device. The LabVIEW API is a perfect match for LabVIEW users, and the DLL API serves users of other programming languages.
  • Memory management is a brand new tool for one of the hot topics, sensor tags, for example. With Memory management, it is possible to verify changes of any memory address content within seconds.

Memory Management

All this said, do not hesitate to contact us! In most cases, it is a win-win situation where you will get your problem solved or a question answered, and we get valuable feedback, which will help us in making our products even better. We are here to help you – send us a message!

Sep 14, 2015

National UHF RFID Standards and RFID Performance

ISO 18000-63 (6C, EPC Class 1 Gen 2) has been by far the most used UHF RFID standard for several years. There have been some competing standards such as Tagidu, IP-X (tag-talks-only), and ISO18000-62 (6B), but they are nowadays rarely used in new applications. However, new RFID standards still emerge: for example, in Brazil, SINIAV has created a protocol aimed for vehicle tracking applications. In China, a new UHF standard, GB/T29768-2013, has been recently published.

Several tag manufacturers work with these new standards. Why do these national RFID standards exist? And what does it mean for performance testing?

Why Doesn’t Everyone Work with the Same Standard?

Since there is a well-working global standard, it would sound logical to use it for as many applications as possible. But there are some reasons for using something else as well. There may be national interests, or maybe there are special requirements that existing standards don’t cover well enough. For example, ISO 18000-63 was developed for quickly inventorying large quantities of items, and it may not be optimal for reading a single tag that is passing by at 180 km/h. Another challenge may be when the tag is in the windshield of a truck filled with other tagged items.

It should also be noted that the division to separate standards does not always have to be final. Commonly, new functionalities and exclusive features are absorbed into the global standard after they are validated.

What is the Difference Between the Different Standards?

When we talk about passive UHF RFID, we talk about readers that radiate between 860 to 960 MHz to power up remote tags, which in turn modulate their reflection to communicate back to the reader. That is common between all passive UHF RFID standards.

The difference is in how the readers and tags modulate the electromagnetic waves, and what kind of command and response sequences are used in the communication.

One standard might be optimized for quick inventorying while another might provide added security.

Besides, the complexity of the protocol affects the power consumption of the chip and, thus, the read range that can be acquired.

What do the National Standards Mean for Tag Manufacturers

So how should a tag manufacturer respond to a customer’s request to make a tag for a less widely used UHF RFID standard? Well, that depends on the opportunity. But there is nothing to be afraid of in the design process – it is no different from ISO 18000-63 tags. The Voyantic Tagformance system supports performance testing of the GB and SINIAV protocols (as well as older ISO 18000-62 and IP-X protocols).

With the Tagformance system, it is quick to characterize a UHF RFID tag regardless of the protocol: just choose which protocol is to be used in testing and then start the selected test. Results include (but are not limited to) information about the tag sensitivity, read range, tuning, and radiation pattern.

Application Developers

New RFID standards are often used in new application areas. With the Voyantic’s Field Engineer’s Kit, RFID tags can be tested within the application – for example, when attached to a vehicle. Vehicles are an example of a quite challenging environment for RFID because of their large metal parts and a variety of different plastic and glass types where tags are mounted. Thus, field test results are crucial.

Typical field tests aim to verify the read range. The Tagformance system can be used in evaluating what kind of read range can be achieved with different readers – without actually using the readers. Based on the tag measurements and the reader information input by the reader, the system shows the achievable read range, but also which tag or reader parameter is the bottleneck for system performance.

Download the Tagformance Pro Catalogue

Learn more about the Voyantic Tagformance® Pro Test Device! By combining RAIN RFID and NFC testing into one compact test device, our all-new Tagformance Pro is a true all-in-one tool for anyone either developing or using RFID technology.

Jul 23, 2015

How to Improve Efficiency of the R&D Team in UHF Tag Design

中文版 Chinese version

Being responsible for sales of RFID performance measurement solutions, I’ve had the privilege of meeting with several companies and their design professionals around the world using very different methods for measuring UHF tag performance. Which is the best method then? I’d say it depends on your requirements – for a single essential measurement, you may use various methods, and even a simple technique can be sufficient. However, if you are looking for a way to improve the throughput and efficiency of your R&D team in tag design, the differences in methods are enormous. So, where does the efficiency come from?

The simplest method in UHF tag measurement is using an RFID reader to verify if the tag can be read from a certain distance or not. This pass/fail type of method is easy to do and fast for sure. However, most of the critical characteristics cannot be measured nor verified at all. Another commonly used way based on a set of generic measurement instruments like a signal generator, a network analyzer, and a power meter, is more advanced but unfortunately not anymore fast nor easy to use.

As the two methods introduced above are not ideal in the first place, neither of them can be the real solution to provide increased efficiency either – don’t worry, there is another approach available.

Purpose-built RFID Measurement System

In the R&D environment, most RFID measurements set high requirements for reliability, accuracy, and repeatability of the results and the test method itself. This is the case also in developing new UHF tag designs, thriving to the best possible performance, and at the same time balancing various requirements for different parameters. In this kind of environment the key questions are;

  • How quickly can a set of various measurements be performed?
  • Can the measurements be repeated automatically during the design iterations?
  • What are the possibilities in storing, analyzing, and sharing the results?
  • What kind of competence is required to perform the measurements?

The ideal solution addressing these requirements is a purpose-built RFID measurement system, providing an easy-to-use user interface, high measurement accuracy, compliance with standard RFID protocols, and wideband sweep capability.

How to Enhance the Efficiency of the R&D Team?

Ease-of-Use

There is inherent ease-of-use in the concept of a purpose-built measurement system, as there is only one tester device, including all the necessary accessories and an easy-to-use graphical user interface. A predefined measurement set-up procedure based on a reference tag ensures correct system start and exact measurement results.

Ease of use improves the efficiency of each user regardless of their technical competence. However, the real benefit comes out of the fact that also less experienced persons can easily be trained to perform extensive measurements without having in-depth RF knowledge.

One System – Several Measurements

A dedicated RFID measurement system includes all the necessary measurement functions presented in a pull-down menu with suggested default settings for each measurement. Wideband sweep measurement performed over a wide frequency range of e.g., 800 – 1000 MHz enables the flexible visual presentation of the tag detuning phenomenon on different materials compared with on-air results.

Measurement functions menu

One Measurement – Several Results

One single measurement, like the Threshold Sweep, provides several calculated results (e.g., Transmitted power, Backscattered power, Electrical Field Strength, and Theoretical Read Range) that can be viewed simply by selecting the desired result view from the Y-axis pull-down menu.

Results selection menu

Repeatability and Automation

Once the user has selected the function and started the measurement with relevant parameters, the test system provides the results that are stored in the results database with a timestamp and detailed information on all the parameters used in the measurement. Error-prone human interaction and handling of the results are avoided by automated calculation and management of the results.

The quality of the measurements can be further ensured by defining and storing a sequence of measurement commands (Scripter) for repeated use. Predefined script together with automatic rotation system eliminates human errors when performing e.g., orientation sensitivity measurements in various positions between 0 and 360 degrees. The example script below defines a sequence of two Threshold measurements and one Backscatter measurement.

Example of a measurement script

Conclusions

A purpose-built RFID measurement system combines high measurement accuracy, versatile measurement capability, and ease-of-use – a unique combination that cannot be achieved with traditional methods.

Accordingly, the improvement of the R&D team efficiency is based on:

  • Quick set-up of the system
  • Better visibility to the performance of the tag under test
  • More measurements in the time available
  • More tests on alternative tag designs in a shorter time
  • Avoiding human errors
  • Testing made it possible for non-RF specialist
  • Shorter time to market for new tag designs.

If you want to learn in detail how the Voyantic Tagformance UHF Measurement System can improve the efficiency of your organization, please download the Tagformance Catalogue below! 

Downlaod the Tagformance Pro Catalogue

Learn more about the Voyantic Tagformance® Pro Test Device! By combining RAIN RFID and NFC testing into one compact test device, our all-new Tagformance Pro is a true all-in-one tool for anyone either developing or using RFID technology.