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Jan 09, 2017

Testing Requirements of NFC/RAIN RFID Dual Frequency Labels in Production

中文版 Chinese version

There are applications, where fast data collection and high read distances of RAIN RFID (UHF) tags fulfill the overall application requirements only partially. Especially the missing capability of a consumer to easily access the tag contents limits the usability for marketing, product information and authentication purposes. A NFC tag would remove that limitation but also induce additional costs and complexity to the label finishing stages: double encoding and possible data compliance verification between these two tags. Interestingly the first IC chip with both high frequency (HF) and ultra-high frequency (UHF) communication interface was launched in 2015 by EM Microelectronics. In this text I will take a closer look at the quality aspects of dual interface tags: How do you verify that each tag produced meets its specification?

Is It Sufficient to Test the Performance of Either Interface to Guarantee the Performance of the Tag?

Let’s dig into the tag structure a bit to understand more detailed where the performance comes from. The chip itself is one complete entity with two interfaces for each frequency. This allows conveniently accessing the memory locations of the chip through either HF/NFC interface using for example your mobile phone, or through UHF interface by for example the retail in-store inventory system. On the inlay level there are still two separate antennas; one that is used for HF coupling and the other for UHF field communication. Both of these antenna structures are connected to the IC through separate chip I/Os. Below we can see an example of such a tag design from Lab ID:

There is certainly some coherence in the process quality for both interfaces, as the antennas are both processed simultaneously, and a single chip is assembled to work with both, but is it enough to guarantee the good performance for both if only one interface is tested? Based on some further analysis on possible failure mechanisms, the answer to the question is

No, it is not!

NFC and RAIN Performance on a Dual Interface Label Needs to be Separately Tested

We ran some tests using both Tagsurance UHF and Tagsurance HF testers to identify less sensitive tags from a roll of dual frequency tag samples. The test setup for testing dual frequency tags consists of two separate Snoop Pro coupling elements – one for UHF testing and one for HF testing – and a Tagsurance unit connected to each of them.

One graphical user interface handles both testing units and gathers the test results and read data from each tag in a combined log file. Based on this information we were able to identify tags with lower performance either on UHF communication or in HF communication. In many failed samples the performance had decreased in both interfaces. In the graphs below we can see the UHF performance on upper graph and the HF performance on lower graph for a normal tag (white curve) and for a tag with decreased performance (red).

This is not always the case though, as we could also identify tags where one interface was performing good, but the other one was either not functional at all, or the performance was just significantly lower compared to normal level of variation in the sample set. In the graphs below there’s the UHF performance and the HF performance of four tags; one normal (white curve), one with decreased UHF performance and normal HF performance (blue) and one with decreased HF performance and normal UHF performance (green). There you can also find one tag with decreased UHF performance and HF performance slightly better than the typical tag (orange).

NFC/RAIN RFID Combo Test Solution Is Available

As always with disruptive new technology, it takes some time for the components and new manufacturing technologies to fully mature. As this brief study shows, the performance of either interface can vary independently of each other, even if they are integrated on the same IC. Therefore both interfaces should be tested in production.

Voyantic provides turn-key solutions for testing of all your RFID production. With our equipment you can test your RAIN RFD tag; HF/NFC tags with ISO 15693, ISO 14443A, ISO 14443B, Felica and ISO 18000 3M3 protocol; and dual frequency tags. We would be happy to tell you more and tailor the best suited solution for your exact requirements!

Download our new Application Note about testing of UHF, HF/NFC and dual frequency tags, giving a detailed understanding on the equipment and test setup used in production. Contact us to learn more!

Learn How to Test Dual Frequency Tags

Download our application note to learn how to get things right the first time when testing UHF RFID, HF/NFC and dual frequency tags!

Sep 25, 2015

How to Optimize the Cost of Quality for UHF Tags?

When talking about high-end RFID performance testing solutions, I sometimes face the situation, where my customer is struggling to find room for the investment in their budget. After some return on investment (ROI) calculation, the case typically looks much brighter.

If we look at the overall quality cost structure in UHF tag manufacturing, I will dare to claim that, in many cases, even a single batch of poor quality can justify the ROI for decent RFID test equipment. The challenge here is though that the costs of being able to provide excellent and consistent quality are directly addressed to the production. In contrast, the charges induced from poor quality are inconspicuously scattered all around the corporate structure.

Where do I base the claim? Let me show you!

First of all, to lower the cost of poor quality, you need to invest in preventing failures and maintaining excellent quality. The great thing here is, though, that you get much more than your money back. If done right, each penny you invest is multiplied as savings in failure costs. This is how you balance the scale and minimize your total costs.

Let’s Do Some Math!

When a quality issue is found in the production, how much does it cost for an engineering team to troubleshoot, or a machine to stand by waiting for the next production batch to be started? I’m sure you know the figures better than I do, but what I do know is these problems take some hours to be solved, sometimes even days. I also know that the one-hour machine downtime in chip attachment makes at least 10 000 tags less manufactured. For a label converting process, it may be ten times more.

What if the problem was not detected when manufacturing the tags, but in an inspection process that was done on the batch afterward? How big is your typical batch? 100 000 tags? 5 000 000 inlays? In the worst case, you need to multiply that with the number of batches produced and with material costs per tag, and add on top of the engineering work and machine downtime.

Ok, now you just need to rework the whole batch, which means again capacity loss, as the machine time is used to reproduce what already was supposed to be delivered. The ball keeps rolling, and you’ll end up with shortages in your next deliveries, delays that cause inconvenience to the customers, and a headache to the management, sales, and customer support. So, just add up the machine time for rework, management, and support time, as well as customer dissatisfaction with the earlier equation.

Now, we are starting to talk about costs that are far more difficult to quantify. Customer satisfaction…

What if the defected batch didn’t remain as an internal issue? What if it reached the customer, who is struggling now with problems in his application? Now we’re starting to talk about external failure costs, which are not only harder to be measured, but also induce secondary effects and costs, like bad quality reputation. I know, impossible to be quantified. But if you just add the management cost due to the complaints and troubleshooting with the customer involved, and forget the fact that the customer may end up ordering his next tags from another supplier, we still have a significant pile of costs due to poor quality. Now would you believe me when I’m saying:

You Need to Balance the Scale to Minimize the Overall Cost of Quality

Unlike the above figure may suggest, the equilibrium point here would not necessarily be where the cost of poor quality equals the cost of good quality. The equilibrium point is reached when the efficient investments in the price of excellent and consistent don’t return more than their value in the costs of poor quality.

The graph below would represent an example situation, where the costs of good quality are linearly increased, resulting in considerable reductions in the price of poor quality at first. Eventually, the point is reached, where further improving the quality appraisal and failure prevention costs will not lower the failure costs as much.

If you calculate with your figures the overall cost for providing just a single batch of UHF tags with inferior quality to the customer, would you agree with me that these costs are just too high to accept frequently, or at all? This approach is only the tip of an iceberg. What eventually will happen, if the quality continuously keeps failing to meet the customer expectations, is you start losing business, surreptitiously, but deterministically.

Quality Reputation – Hard to Estimate, Easy to Forget

The quality reputation is easier to ruin than to be built. Building it from scratch takes time and effort. Trying to gain customer trust without hard evidence based on measured facts is challenging. Still, if you’re able to quantify the quality, as well as prove the quality is consistent, you’re in a wholly different position to win the customer.

We have various examples of customers who have taken the UHF tag quality seriously, all the way from design to production. There are customers like Michelin, who have decades of experience in manufacturing and quality control. They have the same approach in case of any new technologies. Why ruin the quality reputation you have successfully built for years? With Michelin, we worked on something a bit customized to be able to test tire tags that are very heavily over-tuned. Check out this interesting case study:

Michelin — Tire Tags with Consistent Quality

Customer Case Studies

What kind of figures did you come up with on your overall cost of quality? Would you like to talk more about balancing your scale as well? Please contact us, and let’s figure out how we could lower your quality costs and increase your profitability! For the first 20 people to contact me, I promise to make free of charge tag measurements.

Solutions for RFID productions

Jun 29, 2015

High Performance UHF Tags with Shorter Time to Market

The majority of the UHF inlay designers have already come to realize that the right measurement solutions are the critical factor for seeing all you need on the UHF inlay performance. There’s not much of those guys anymore, who run around with the tags, checking with a reader how far you can go until the tag can’t be read anymore. Not only is this kind of measurement inaccurate, but it also doesn’t give any indication of what kind of changes are necessary for the next iteration in the design.

In my work as a Product Manager at Voyantic, I have seen the accurate, communication based, wide frequency band measurements for the UHF tags become more or less the de-facto standard of the industry in tag design. Now I’m happy to see the tag manufacturers widely adopting the performance testing also in production quality assurance.

So from design to production – why should you measure tag performance?

Quality from Design to Production

The measurement solution giving visibility to the UHF tag performance throughout its wide operation frequency range helps the designer to see exactly how the tag performs and understand what modifications are required to improve it. This enables faster development cycle times by providing high-performance UHF tag designs with shorter time to market.

This same yields to the production quality as well. Let’s take an example of a new product introduction, where an inlay design is brought to the production floor for the first time. If the RFID test equipment in the manufacturing machines can only tell whether the tag is functional or not, the batch will typically be taken to a very comprehensive and time-consuming first article inspection in the lab.

Imagine the reduced downtime!

If the samples are analyzed in the lab, not only does it take much time, but also the corrective actions can be implemented after this detailed analysis step. Imagine making a similar analysis on the production floor during the first batch manufacturing. Making the fine-tuning of the process on the go and reducing the time to market and machine downtime. In addition to the high-speed process compatible performance testing, the Tagsurance UHF testing equipment can also handle this more detailed analysis job.

Performance testing reduces the overall cost of quality without creating a bottleneck to the process.

Regardless of the process, there are always benefits in the performance testing of the tags. In the chip assembly, it is clear, the performance of the tag is created in this process when the chip is attached to the dipole antenna structure. In label converting, the main thing is to verify that this performance is maintained, but a reader can only check the tag still functions. The functional testing does not allow visibility in what is going wrong when the failures start occurring, and it can’t detect all the abnormalities and poorly performing tags, which then end up in the application use.

With the right tools, I’ve seen young startups reaching the same quality level with their UHF tag products as the big players of the market in no time. Without having to go through years of learning, in the worst-case learning from the failures noticed not until in the end customer application. This is the critical thing when balancing your overall cost of quality; investing in quality appraisal and failure prevention will spare your investment many times in the failure costs.

Let’s Take the RFID Industry to the Right Direction

Together! I have had the pleasure of working with so many quality-conscious RFID experts in the past years and have enjoyed seeing how much improvement you can make with the right tools in a short time. The increase of interest in production quality and implementations of Tagsurance UHF RFID testing solutions during the past year has made me gain confidence in the UHF RFID. It will no doubt be the technology to enable reliable, repeatedly functioning applications, without component level surprises in the application piloting stage.

Thank you for your interest! If you have any questions or want to start a discussion on how you could improve your RFID quality, let’s talk more! If you want to learn more detailed on what type of test data you could achieve in production, download the full sample roll test report below.

Learn Exactly What We Can Find Out on a Roll of UHF Tags!

Download a full Voyantic sample roll test report with full visibility to the performance of each and every tag on the roll, far field measurement results on selected tags and optimized production test scenarios for different process throughputs.