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RAIN RFID 101 for Label Converters – Webinar Recap

May 31, 2023

As the demand for RFID smart labels is growing, traditional label converters are increasingly getting questions from their customers about adding RFID to their label products. 

Label converters that are just starting with RFID or considering it, need to first educate themselves on the fundamentals of the technology and what is involved in producing RFID labels. We decided to host a webinar to help with this first step.

Watch the webinar recording ›

Or read a summary of the main points below.

RFID Market is THE Market to Be In

The RAIN RFID market is developing in terms of volume, value, and diversity. Big retailer mandates, such as the Walmart mandate, also have an effect on driving growth on the retailer side, creating opportunities and challenges for the players in the market. Likely, your first RFID label customer will not be your last one. 

The webinar focused on the basics of RAIN RFID specifically in the context of label converting in the retail industry: what are the key aspects that a label converter needs to consider when adding an RFID inlay into labels, turning them into RFID labels? 

The webinar also touched on data standards and data encoding. Knowledge of encoding and different data standards is the key to preventing tag clutter which can be an issue in the RFID industry, but also to enabling the use of the item’s digital identity throughout its lifecycle. For example, the same RFID tag can potentially be used in various different applications from logistics management, and inventory tracking in the store, to customer self-checkout, and customer experience applications. 

There are a lot of great resources available for the basics of  RAIN RFID technology, its applications, and its unique benefits. If you are a RAIN RFID beginner, https://www.rainrfid.org is a great place to start.

How to Approach the Increased RFID Label Demand?

The typical steps that label converters need to take to get into the RFID label business include:

  • Acquiring information and knowledge
  • Expanding supplier and partner networks
  • Upgrading different production machinery for RAIN RFID
  • Investing in dedicated RAIN RFID production machinery

The first step always is to acquire information. What does your customer need and is there a mandate or any other requirements documentation that you need to familiarize yourself with? What is the format of the label that is needed; a sticker, a hangtag, or a prime label? What kind of data is needed for the label, both printed and encoded? 

You will also need to learn essential information about RFID technology and RF-specific considerations for the label production process. Inhouse expertise on RFID and any applicable mandates is highly recommended, in addition to finding the right partners. An in-house expert enables you to become a value-added supplier to your customer to navigate through new requirements from their retail customer. 

Read on to get started with the first step. 

 You can recognize an RFID label by an RFID or EPC emblem mark on the label or hang tag. EPC stands for electronic product code.

What do you need to know about RFID inlays?

One of the core components of an RFID label is an inlay, which consists of an antenna on a substrate and an IC (chip) glued on top of the antenna. This process creates dry inlays. Dry inlays do not have an adhesive layer.  

A term you often hear related to retail label mandates is white wet inlay, also known as a “sticker”. A sticker refers to a blank RFID inlay that has adhesive and liner layers and a simple white facestock. A sticker can be applied directly to an item.  

  • Dry inlays: no self-adhesive layer in the inlay. I.e. it is not a sticker
  • Wet inlays: an inlay in a sticker format with an adhesive and liner layers, and it can be directly applied on top of an item without additional converting process
  • White we inlay aka Sticker: an inlay in a sticker format with adhesive and liner layers, and a white facestock

Overview of the RFID Manufacturing Process

RFID label converting includes unique requirements and considerations for the converting process. Before going into the converting process, it is essential to have at least a high-level understanding of the entire RFID manufacturing process and how converting relates to the process. 

  1. Without going into component manufacturing (IC, antenna, liner materials, etc.) the first step in the process is chip attachment (aka IC bonding)  where the IC is attached to an antenna to form an uncut dry inlay. There are specialized manufacturing companies that focus on IC attachment to produce inlays.
  2. Next, the uncut dry inlays are converted in one or more process steps into labels:  material layers, and adhesives are added, and labels are cut into white labels, aka stickers. This simplified process is just one option and there are a lot of different processes for RFID label converting, depending on the type of label and use case. 
  3. After converting, data needs to be added to the blank label. This process is called personalization and can sometimes be done on the same label-converting line. Data is encoded into the labels to give them a unique serial number that can be read with RAIN RFID readers. Personalization also includes printing human-readable data and information on labels. 

The last step of the process is attaching the ready label to an item, and turning it into a tagged item.

For a converting company, the business opportunity is anywhere between dry-cut inlays and personalization. This strategic decision impacts the label manufacturing process changes and machinery investments that are needed.

Retail RFID Mandate Data Terminology

One of the growth drivers for RFID labels is coming from the big retailers mandating the use of RFID for their suppliers. There are some basic terms you need to be aware of, specifically related to the retail mandate landscape.  

When your existing customer is asking for RFID labels for item identification, in terms of data, you will need to convert the products’ UPC / EAN / GTIN barcode number to an RFID encoding and add a serial number. The combination (barcode number + serial number) is a unique EPC, which is the GS1 term for an RFID-encoded number and stands for Electronic Product Code. 

Source: https://site.gs1us.org/rfid-creating-epc.html

The retail world has traditionally focused on using barcodes to identify the product type (stock keeping unit, aka SKU), for example, a 5 lb bag of flour or a 1 gallon of milk. This is now changing into having a unique identifier for every single item. By adding a serial number to the product label, you don’t just know the product type, but exactly which individual product package it is. This naturally requires that every single serial number is unique. You should always use official RFID tag data standards/numbering schemes. 

One term that comes across in the retail mandates is “permalock”. Permalocking the encoded RFID data means that users cannot change the data. RFID tag data can also be “locked”, but locked data can be re-written with a password. Permalocking the tag data is required in most retail mandates. 

  • UPC = EAN = GTIN = barcode number
  • EPC = GS1 term for RFID-encoded number
    • EPC or ISO RFID logo is usually required to be printed on the labels to indicate to consumers that the label includes an RFID tag
  • SGTIN-96 = Encoding scheme that includes GTIN and the serial number. The number 96 refers to the number of bits in the tag chip where the information is encoded
  • Permalock = RFID encoded data is permanently locked so that users cannot change (re-write) the data

How to Get Started

In short, you can get started with the following steps

  1. Source inlays
  2. Get machinery to insert/laminate RFID inlay on a sticker or a prime label
  3. Add quality control
  4. Find out if encoding is required. If yes, get encoding equipment and data models

Inlay Selection

In some cases, the mandate specifies the type of inlays that can be used. If the inlays are not specified by mandates, often there are de-facto inlays that are being used in particular industries and applications. Inlays specified in the mandates are selected through quality certification processes. 

Auburn University ARC certification program works closely with big retailers to establish quality standards and performance requirements for inlays in various applications and environments. Those requirements are defined in requirement Specs maintained by ARC. The ARC program tests inlays against the requirements in the Spec, defining and listing which inlays are approved for that Spec.  

Retailers can check which inlay Spec applies to different product categories and which inlays are approved to meet the performance requirements for that Spec. 

Source: https://rfid.auburn.edu/walmartspec/

However, not all retailers use the ARC specifications. Some have in-house specifications and documentation that specify which inlays are accepted. 

Most mandates define the dimensions of the finalized RFID labels and specify the performance of the inlays by referring to the ARC categories.  Typically there are multiple options for inlays that meet the requirements available. An important consideration is to take the converting machine capabilities into account; 

  • what size rolls can be used in the machine, 
  • what should the roll core diameter be, 
  • should the inlays be cut or uncut, 
  • do you need dry or wet inlays, etc? 

These practical considerations may limit the selection of possible inlays and their delivery format. 

Other considerations for inlay sourcing may include pricing, delivery terms, and schedules, support availability from the inlay supplier, available quality data of the inlays, etc. 

Label Approval

Next, you need to figure out the label type required by your customer. There are different types of RFID labels, prime labels, hang tags, and stickers. RFID tags can also be embedded into the product or packaging. In retail, a sticker, which is an RFID label with a simple white facestock, has become a common way to add RFID to products. The retail mandates may also define requirements for the sticker facestock and adhesive materials. 

A typical RFID sticker on a product packaging

Next, your customer needs to have the finished label go through an approval process in which the retailer can verify that the labels are encoded properly, contain all the required printed information, and are positioned properly on the product. Auburn University’s ARC program covers the label approval process for most retailers. Not all retailers go through the ARC program, however, they may also have their own internal approval process.

Another term you may run into is GS1 TIPP, which stands for Tagged Item Performance Protocol. In the TIPP approach, instead of testing tags or inlays, the testing is done with the item that is already tagged with RFID. TIPP is used for some mandates in Europe and its use is also increasing in North America, especially for the use of food and pharmaceuticals. 

RAIN RFID Production Machinery – Upgrade or invest in new?

RFID inlays are a layer of materials. If a converting machine has an insertion capability or a laminating capability and a die-cut station, those machines can typically also be used for inserting RFID inlays. But there are a few considerations to keep in mind. 

For dry inlays that don’t have any material on top of the IC, ESD (electrostatic discharge) protection and tension control should be considered. A common reason for IC malfunction is either too loose or too high tension for the inlay roll. If the roll is too loose, it can slip and break off the IC. If the roll is too tight and there is too much tension, it may crack the IC or IC connection. A proper quality control system is the only way to know if something is going wrong in the process. Real-time visibility of each label’s performance allows adjusting the process parameters as soon as problems are detected, eliminating waste and re-runs. If a machine has some kind of tension control or some kind of ESD protection, typically that also works for RFID. Wet inlays with material protecting the IC and antenna, are well protected against tension and ESD.

The other option is to invest in new RFID-specialized converting machines. This may become an option to consider as you grow your customer base and you need to scale the production. The good news is that there are options and expertise available to help you with your choices.

Add Quality Control

Inlays are not continuous material, which makes position control critical. The inlay must be in a consistent position inside the label, and must not be cut or perforated. 

Quality control for RFID labels differs greatly from quality control for traditional labels. Unlike barcodes, which can be verified and checked visually, RF performance cannot be seen. An RFID label that works well usually looks exactly like a label that does not work as specified.  

The RF performance of the label needs to be tested to make sure it works within set performance requirements. An RFID tag may be readable, but the performance may not be good enough causing variation in the read range that is not acceptable for the intended use case. Read range is the distance that a tag can be detected with a reader. In other words, a tag may be readable in the production line in close proximity, but may not work when attached to an item and read with a handheld reader from a few meters apart in an inventory count. 

Monitoring the performance of the tags is not complicated. It can be done in the production line at full production speeds, checking that every label on the line meets the specified performance requirements. The quality testing system brings visibility into the process, making sure you also catch any issues early on in the production run. 

Encoding Equipment

RFID labels can be encoded either inline with encoding equipment integrated into the converting machine, with specialized roll-to-roll encoding machines, or using RFID printers. For large volumes, the ideal would be to encode inline and at high speed. RFID printers can be used as a temporary solution for larger volumes, short-run service bureau jobs and for low- to mid-volume stickers and prime labels that can be accommodated in a printer. 

Stay Tuned for the Next Webinar

If you made it through to the end of this post, you might be interested to hear that we are planning a follow-up webinar that will dive deeper into the RFID label converting process. You can help us plan the content and make it more relevant to your needs by sending over any questions or suggestions related to the topic.  (email: marketing@voyantic.com)

And make sure you’ll get the webinar invitation by signing up for our blog updates → 

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Voyantic Announces the End-of-life Schedule for Legacy Tagsurance and Reelsurance Products

May 23, 2023

Voyantic Tagsurance® 3 replaces older Tagsurance products.

Voyantic Tagsurance® 3 is the new generation production testing system that replaces Voyantic Tagsurance 1 and 2 systems.

Today Voyantic announces the end-of-life schedule for legacy Voyantic Tagsurance and Reelsurance products as follows:

The last order date for the following listed products will be June 28th, 2024

  • Tagsurance UHF 1.0 hardware
  • Tagsurance 1.x software
  • Tagsurance 2.x software
  • IO controller with 6-channel multiplexer hardware

The last order date for the following listed products will be November 24th, 2023

  • Reelsurance lite
  • Reelsurance Pro
  • Note: Reelsurances can be bought from Reconcile Engineering

There are no planned software updates for Tagsurance 1.x or Tagsurance 2.x software or any other software, firmware or hardware related to the above-listed products or product components. The last versions of the software are listed below. There will only be critical patches made if necessary.

  • Tagsurance 1.10.2
  • Tagsurance 2.6.4

Technical Support Continues

Technical support, calibration service, and spare part availability for all products affected by this announcement will continue 7 years from the announcement (until 28th June 2030).

Tagsurance 3 replaces all the core functionalities of the announced end-of-life products

Compared to Tagsurance 1 and 2 UHF and HF quality testing on production lines and machines, the Tagsurance 3 System offers:

  • All the functionalities included in the legacy systems plus many improved functionalities
  • 2-3 times faster operation for UHF testing
  • Much easier integration to almost any production line or machine
  • Complete REST API (+streaming) for data integrations
  • Machine IO for digital IO integrations with production line or machine PLC (e.g. stop at splicing table at lot end, stop/signal at low yield, etc.)

Reel-to-reel / offline testing (Reelsurance)

Various machine vendors offer similar reel-to-reel machines where Tagsurance 3 can be integrated. Contact our sales team for assistance.

What about the “manual test station” and Bendurance?

Voyantic Bendurance and the manual test station for Tagsurance 3 will remain available. See Tagsurance 3 product catalogue Q2/2023 (pages 38 and 40).

Do you need help with figuring out the changes needed in your machine or other integration?

The Voyantic technical sales team is more than happy to help you get your journey started for upgrading to Tagsurance 3. Please contact sales@voyantic.com.

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Testing Tags for ETSI EN 302 208

May 05, 2023

We are getting a fair amount of questions on “how to approach ETSI EN 302 208” and I figured I would first give you all the painful details and then summarize what I believe is the right advice. My message is: EN302 208 testing can be made really fast and easy. Read on to find out how!

A bit of history

Right from the early days of the European Union and the UHF band RFID, the “EN 302 208” has been the well-known and unified standard describing how to set up and test RFID equipment to be declared as radio devices in Europe.

The first version was published back in 2004 describing reader requirements, but also briefly touching on the subject of RFID tags by setting a limit for their out-of-band spurious emissions. Most probably this was taken more as input by reader designers to limit Back Link Frequency (BLF) in their ETSI mode, and not really as impacting the work of tag designers. After all, it’s the reader that sets the carrier frequency, and power level and has command over all of the tag’s settings, right?

Well, nine standard versions later we are now at v3.3.1 which has limits for both tag out-of-channel emissions as well as outright limits for backscatter levels both for the ~865 MHz “lower” and ~915 MHz “upper” band ETSI channels. In the last few years, tag manufacturers’ interest to produce and offer labels fulfilling the standard has steadily grown. Most probably as a result of RAIN technology entering new market verticals with longer and stricter traditions of following all kinds of standards.

Feels a bit complicated, why is it so?

The standard has been a tough one for tag manufacturers to decipher as it is written in the form of a traditional EMC standard talking about power spectral densities, transmit masks, and resolution bandwidths.

This makes it harder to compare the limits against more typical RFID tag results that we have gotten accustomed to, such as “power on tag reverse”. However, the greatest layer of fuzziness comes from the fact that the standard is a generic standard, as it understandably needs to be, providing absolutely no help in associating the tests with RAIN technology, GS1 Gen2 protocol, and the equivalent ISO counterpart 18000-63 that 99% of all the UHF tags utilize. This unfortunately leaves a lot of room for interpretation.

The actual test to be performed, according to the standard, sounds relatively straightforward: 1) Radiate the tag by a field strength equivalent to 2W ERP from 20cm away. 2) Record the tag’s modulation spectrum. 3) Compare against limits. Well, a tag doesn’t backscatter anything on its own unless a proper command is given. So, a command is needed in the form of Query, Query+Ack or Query+Ack+ReqRN+Read. For the lower band a BLF of ~300kHz should be targeted and for the upper band ~600kHz. In Gen2, these in practice will often be rounded up to 320kHz and 640kHz as those are the frequencies that all tag ICs can divide their clock down to. The problems arise trying to capture the tag’s response with a spectrum analyzer. The response is always very short, typically only a few hundred microseconds and inconveniently only some 30 µs apart from the immensely more powerful command itself. Accidentally analyze any part of the command or any part of the silence after the tag’s answer and the outcome will be hugely incorrect.

So what is left for interpretation?

According to the standard, the answer should be recorded with a resolution bandwidth of 1kHz around the carrier frequency. This indirectly implies that the answer should be much greater than 1ms for this to be even theoretically possible. So, the exact correct resolution bandwidth can rarely be used except for some high Miller modes in combination with the lower ETSI band’s lower BLF.

This brings us to the perhaps biggest question: Which modulation type and data content should be used in the tests, and is the test supposed to be passed for all of these modes, a typical one, or for any selected single mode of use? The difference in passing or failing the test can be as big as 15 dB between these several modes! In simple terms, a tag that always modulates with a fixed amplitude between the same two impedance states while backscattering will always produce an equal amount of total backscatter power. What is different, is how spectrally spread or focused this power will be. And for the ETSI test, what is recorded in the end, is the strength of the peak spectral feature. So, it will be much easier to pass the test with the power spread across the frequencies as evenly as possible. 

Let’s compare the spectra

The absolute worst case for the ETSI tag emission test will be a “continuous square tone”. That is, a symmetric square wave modulation as in the case of sending a long train of data zeros with FM0 decoding. The same square wave modulation also happens in the miller modes when the extended preamble is requested by the reader. The square-wave backscatter modulation of the tag will create a Fourier-series type of spectrum with almost all of the power concentrating on exactly carrier +/- (n*BLF), where n is an odd integer. This is the absolute most difficult mode to pass the test with and that’s why in the Tagformance system this is referred to as the “worst case” from release version 13.5 onwards. Pass this and you will pass everything else too with no need to test for anything else.

Comparison of spectra of equal power backscatter signals with different coding type and data content.

Ironically, if FM0 is the “worst case” to pass, it is also the “easiest case” when the packet data is randomized. Having a roughly equal distribution of zeroes and ones in random patterns will with high probability create a very spread out spectrum. A spectrum with no predictable high peaks which could breach the mask and fail the test.

Somewhere between the worst and easiest cases fall all the Miller modes producing their tell-tale double-peak “rabbit ear” spectra. Miller modes, ranging from M2 through M4 to M8, are often favored by the readers for their decode sensitivity. This is why we have chosen the M4 with a randomized data packet to be our most “typical case” for tag emission testing.    

The Voyantic way

Currently, Voyantic offers two approaches in the Tagformance system to test for tag emissions. The perhaps more traditional and thorough approach makes use of a separate calibrated Rohde-Schwarz spectrum analyzer which is synchronized to the Tagformance system to record just at the correct moment and for the correct duration to hit the tag answer.

The alternative method is the “simulated spectrum” method, as it is referred to in the Tagformance user interface. Despite its name, it is a tag measurement, where the tag backscatter is measured for amplitude and frequency. The point where a measurement turns into a simulation is when the measured parameters are taken to recreate a prototype of a waveform, the spectrum of which is then evaluated against the mask limits. The simulation assumes a sharp backscatter modulation between two discrete states utilizing a random data packet which is selected to be as average and representative as possible. This is very close to reality, and what is important, is that the reality can only be more forgiving. So, if you pass with the simulation, you will pass in the spectrum analyzer measurement too. The great advantage of a recreated data packet is that it can be created to be of any suitable length and thus analyzed with any resolution bandwidth.

A simulated backscatter spectrum in relation to the ETSI limit in Tagformance. A finer ResBW of 1kHz is used in the central 2MHz according to the standard.

Conclusion

An easy option is to take the EN302 208 testing as a part of the design process as the testing can be made really fast and easy. It is adequate to use the simulated mode as in reality, things are not going to be worse. So if you pass, you pass.

This really means that the measurement system and setup are exactly the same as you would use for tag measurements.

Using Tagformance Pro and a Voyantic measurement cabinet, the result is just a few clicks and a few seconds away at any given time. Simply place the tag on the measurement platform as you would with e.g. threshold or read range measurements and run the tag emission test.

Finally, Just wanted to take this opportunity to mention that our C50 cabinet has a really nice very-low-echoic rotation system, and having a Tagformance Pro and C50 on one’s lab enables truly complete measurement capabilities from basic frequency response (threshold, read range) measurements to EN302 208 and ARC pre-testing. All in one system, easy to buy and use – and to maintain for several years to come.

Ah, one more thing, get the latest version of Tagformance Pro UHF software to have the well-recommended “typical” simulated results at your disposal! No spectrum analyzer? No problem!

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