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Passive RFID Sensors and Tags with a 100m Read Range A Geeks Report from RFID Journal Live! 2016

May 20, 2016

中文版 Chinese version

Two weeks ago was again the time of year when the RFID industry met at RFID Journal Live! in Orlando, Florida. The show is one of the main events of the year for Voyantic as well. But what were the hot topics this year?

As always, several new products were presented at the show. A significant trend for the last few years has been UHF RFID finding its way into mobile phones, first as add-on modules, but now also integrated into the phones. Another new product category was inventory robots that were seen roaming the aisles of the show. Mikel Choperena of Farsens writes about these trends in more detail in his trade show review.

Industry-wise, the airlines seem to be currently on the up in RFID adoption. Delta was one of the keynote speakers of the conference, and several companies were presenting SAE AS5678 certified tags meant to be used in airplanes. But other industries, such as manufacturing, healthcare RFID, and retail were also well represented.

Passive Sensors Steal the Spotlight

After last year’s show, I wrote that one of the hot topics was (link: text: passive RFID sensing popup:yes), and noted that sensing occupied four of the ten Best New Product nominations.

It looks like sensing picked up where it left off last year.

This year’s award was shared between two innovative sensing products:

  • The first winner was SMARTRAC Technologies, for its Sensor Tadpole, a passive UHF sensor that can detect the presence of moisture. The sensor tag has been used by automobile manufacturers for ensuring that the cars leave the factory watertight.
  • The other winner was Phase IV Engineering for its RFID Sensor Reader, which is designed to collect accurate data from passive RFID sensor tags. Think of it as the missing piece that links passive RFID sensors to industrials PLCs, converting sensor readings from a tag’s memory to industry standard voltage or current levels. Keep your eye on this company!

Bubbling Under in the Academic Scene

RFID Journal Live! was co-located with several smaller conferences, one of them the IEEE International Conference on RFID, “the premier conference for exchanging all technical research in RFID”. My colleagues were kind enough to relieve me from booth duty, so I had a chance to attend the conference, and spend some time with my fellow geeks.

This year was the 10th occurrence of IEEE RFID, and I can proudly say that I have participated in pretty much all of them in some role: in the Technical Program Committee, as a session chair, or as an invited speaker. The conference covers different aspects of RFID research; this year the largest amount of presentations fell under the categories of

  • antennas & propagation
  • circuits
  • devices & readers
  • protocols & security and
  • energy harvesting & wireless power.

For me, the most interesting talk was given by Dr. Greg Durgin of Georgia Tech. He received the best paper award for his paper titled “RF Thermoelectric Generation for Passive RFID”. The paper proposes a new way to power passive tags based on thermoelectric generation instead of traditional diode rectification. To put it in perspective, Alien Technology presented their new Higgs-EC tag IC at the show, reported to have best in class read sensitivity of -22.5 dBm with a dipole antenna. Dr. Durgin’s proposal could bring sensitivity down to -34 dBm, allowing read ranges of up to 100 m.

Think about all the applications that a passive 100 m read range could allow.

RFID has definitely not seen its limits yet!

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Designing a RAIN RFID Sensor. Simple, or Is It?

Mar 23, 2016

中文版 Chinese version

Combine identification, sensors, low cost and years of life time together and you certainly end up with a disruptive mixture that is set to boil over in the near future. RAIN RFID sensors may not be a huge market just yet, but we can see many companies putting a lot of development effort on them. Read on to see an introduction to the six topologies that I’ve seen utilized so far.

1) Affecting Antenna to Chip Matching

Right from the beginning of the UHF RFID, engineers have been aware of the inlay antenna’s sensitive nature to change its parameters whenever just about anything changes in its proximity. So, it didn’t take long for scientists to call it a sensor. No added energy was wasted on sensing electronics, therefore potentially long sensing ranges were expected. In practice, however, these type of sensors never got too much of a foothold on the market, as the tags were still sensitive to many measurable parameters, and not just one.

The impedance of the antenna is affected, making a detectable change in frequency tuning, activation power, or RSSI.

2) The Dual Tag Relative Approach

To address the real world problems of the previous approach, a simple improvement was soon used. This time, two similar inlays were encapsulated into one physical tag casing, but one of the antennas is made more sensitive to one particular property. For example, if salt impregnated foam is placed over one of the inlay antennas, it doesn’t affect the antenna when dry. However, when humidity rises, it will deteriorate the performance of this antenna at a much faster rate. The reader would poll both of these tags, typically of a sequential EPC code, and monitor the difference between the two RSSI levels.

The impedance of one of the antennas is made much more sensitive to the parameter to be measured.

3) The Embedded Tag

A few years ago the most common type of sensor tag was the embedded type of tag. In this form one or several sensors and inputs can be monitored, logged into memory and read from there when needed. Practically any type of sensoring can be performed in this way, but the solution requires a battery. Although the battery does not sound like a too bad thing to have inside, however the advantage to other technologies, like Bluetooth LE, is rapidly lost. There are also several RFID chips that work with the same principle, but alone without a separate microcontroller.

The RAIN tag uses an I2C interface to interact with a separate sensing circuitry. All this requires more power that the tag can harvest from the RF field, thus a battery is added.

4) Using Automatic Chip Impedance Tuning

Adaptive chip impedance tuning was long awaited, and finally RF Micron was among the first to arrive to the market with a chip with that capability built-in. It didn’t take long till it was used to detect changes in the antennas proximity just like in the case 1. The biggest difference is that now the sensing result can simply be read from the tag memory and not from the RF properties of the tag.

An RAIN RFID IC with automatic chip impedance tuning capability stores the data in the tag memory where it can simply be read with a reader.

5) Binary Sensing

Several ICs have a special pin called the tamper detection pin. Whether this pin is in contact with ground or not can be polled by the reader. It is thus not so difficult to turn this tamper function into a sensor with a bimetallic strip, mercury switch, level float, magnetic switch, NTC resistor, etc. The fact remains that this topology of sensor remains binary.

ICs with tamper detection can be turned into a binary sensor with relative ease.

6) Inbuilt Sensing Capability

To bring potential cost down and optimize the energy consumption of the tag, the sensor is best integrated into the RFID IC itself. As no busses, microcontrollers, sensors, etc. need to be powered externally, the reading range can be potentially close to that of industry standard tags. The range of measured properties are more limited with this approach, temperature being the simplest candidate.

Built-in sensors can be powered from the RF field without a battery.

All this is to say that RFID sensoring can, in fact, be really simple. However, to get the solution working right also on-site with a known level of sensing accuracy requires advanced methods and a correct set of tools.

Getting It Right With Proper Tools

A number of RFID sensor developers are already using diverse functionalities in the Voyantic Tagformance systemto accelerate tag development cycles, optimize designs and to characterize their products. The more data there is in the sensor tag datasheet, the easier it is for anyone to take it into use!

If there is a particular type of testing you need to get done, but cannot find that particular function in our software GUI, please do not hesitate to contact us! Check out also our earlier blog post of passive RFID sensing!


Learn How to Design Passive Sensor Tags

Download our application note “Utilizing Voyantic Tagformance to Speed Up Development of UHF RAIN RFID Sensor Tags” to learn how to design passive sensor tags!

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Helping The Boss to Arrive at the Correct Decisions; In-house Selling of RAIN RFID Test Equipment

Jun 12, 2015

中文版 Chinese version

Selling is a noble form of art, which takes slightly different forms when selling to a customer (out-house) or a colleague (in-house). Luckily both the directions go by the same principles. The twist in general is whether that special someone is already looking for a solution and is therefore on the buying mode, or not looking and even in the I-have-other-priorities-such-as-protecting-the-cash mode.

As my company Voyantic operates in the relatively young technological field of RAIN RFID measurement and testing solutions, the latter mode is usually assumed, since the prospect companies are typically start-ups. Of course, we are not working on the sales case only from outside the prospect company, but together with an in-house sponsor that faces the same communications challenge: How to get the management to say yes to the investment proposal?

The Boss Takes the Most Heat in the Valley of Death

Our prospect start-ups are in the pre-launch phase, and cash flow vice is located firmly in the valley of death. I’ve been in that valley myself – it’s a horrid place, and only the brave go there.

Sales is all about getting to Yes. Let’s, therefore, focus on The Boss, because ultimately she/he says “Yes” or “No” to the investment proposal.

The Boss is a creature with three primary functions: stay as a boss, carry the grave responsibility, and make decisions when needed. One way to initiate a decision-making process is to spread a certain amount of fear powder over the responsibilities part. Some others prefer to play this card right the opposite direction: paint a fresco of stunning business performance and thus suggest the marvel of getting out of that valley sooner than later, and this way become a happier boss.

One Boss in the Valley of Death, under wildlife attack, not enjoying the moment very much, and thus motivated to make decisions

Facing RFID Sensor Tag Development Hurdles

To make a case of the latter, let me walk you through a hypothetical example of in-house sales: Assume you are an RF antenna engineer in Company Z that is developing a novel RAIN RFID tag with disruptive never-before-seen sensor features.

Cutting edge stuff, and riding high on the hype curves, too! So it gradually reveals to you that the antenna design is heavily restricted by the selected production process, which further seems to limit the tags reading performance. Unfortunately, you don’t quite have all the facts on the table to back decision making, because there is only a DIY RFID reader based test setup in the basement lab, right next to the janitor’s room. Additional discomfort arises from the fact that the latest tag sensor circuitry samples seem to have a set of “undocumented” properties that don’t go so well either with the reader in the lab.

The sensor tag launch date is set only ten months away to a RAIN RFID show taking place in Orlando (sometimes in San Diego), and the marketing lady with the scarf is making preparations already. Even the product brand name is already registered.

It Doesn’t Hurt to Find Out How Others Have Managed to Get the Antenna Design Right

Let’s face it – those are hugely expensive ten months for several reasons.

First of Company Z has only the slideware to sell, which means there is practically no revenue.

Secondly, there are you and both your buddies in the lab ordering materials, scissoring inlays, 3D printing prototype enclosures, cursing the air conditioning, and wishing all is going to be ok.

Thirdly, some other companies in the market are already launching their first sensor tag products, which is irritating because you know they are bluntly eating off the yours-to-be market share.

So, being a bright and open-minded engineer, you take a few hours on Tuesday to browse through a pile of academic publications on UHF RFID tag design. While your coffee mug gradually sinks below the refill level, you suddenly realize all those papers refer to this one RFID performance test system.

Switching over to Dr. Pepper and taking a few additional hours to complete the desk study, you find out that this stunning equipment shows how a UHF tag is tuned in about 30 seconds and also how the IC responds to different commands. On top of that, it dawns on you the system is available with two weeks lead time, and the supplier even has a tag production quality test solution, too! Tuesday well spent!

How to Present the Gathered Information with Maximal Impact

So what is it that you do? Well, first, you go home and sleep off the first wave of excitement. On Wednesday morning, you make a few calculations together with a fresh blueberry muffin, then rush to the corner office at 9:15 AM, take a deep breath, and…?

At this point it is important to remind yourself that The Boss is in heat and busy looking for a way out of the valley of death.* You are almost there, next reel it in with a correctly tuned message*:

  • JUNIOR MISTAKE: just ask The Boss to buy this one great tester worth 50k
  • MILD, BUT MIGHT WORK: explain how you found a way to raise RnD efficiency by up to 22%
  • MUCH BETTER: tell you found a way to get the tag design finished in time, AND troubleshoot the damned sensor circuitry while at it
  • A NO-BRAINER DEAL: report to The Boss that you found a way to cut time-to-market by 50%.

The lower on this list you are able to go, the smoother response there will be on your closing line about the investment.

In a Competitive Environment Time-to-Market Makes a Grand Difference

Essentially you should show that you can make this massive difference on the top line if this enabling 50k investment is carried out now, and sales would start sooner than later. Bring in a few of those academic publications with you as evidence, and ask the measurement system vendor for payback estimates and additional collateral, such as a few reliable customer references.

The Boss knows the painful cost and agony of those ten months, and if you claim you can save 5 out of those, he figures out it’s going to be three months saving with a reference customer as a cherry on top, and he is going to sign you those 50k pretty darned fast. All top bosses know that you need to spend money to make money, and just kindly remind that waiting is the most expensive alternative of all.

Wrapping It Up: Investment on Test Equipment Often Turns Out to Be an Investment on Sales

The payback on measurement and testing equipment investments are exceptionally fast when the impact hits the frontlines of the sales battlefield. “The cutting costs” story may work reasonably well in large companies. Still, when it comes to shortening time to market, fixing diverse quality issues, and creating positive aura on the customer front, it all quickly translates into getting additional revenue for the company, sooner than later.

All top bosses love the additional revenue. Cards well played, and you just got your first Voyantic Tagformance.

That’s my story for you today. These principles have worked out well for me many times, and I would love to hear about it if they work out for you as well. Please drop me a line at, and let’s talk more.

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Is Now the Time for Passive RFID Sensing?

May 29, 2015

One of the hot topics at this year’s RFID Journal Live! trade show in San Diego was passive RFID sensing. The show featured several new sensor products from companies like RF Micron, Smartrac, Phase IV Engineering, Farsens, and many others. But what is passive RFID sensing all about? And should you already be working with it?

The rise of passive sensing has been noticed by other people as well. Mark Roberti, the founder and editor of RFID Journal, gave special mention to some of these solutions in his article.

As a matter of fact, four out of the ten Best New Product nominees at the show were related to passive RFID sensing.

In addition to the announced new products, there seemed to be a lot more bubbling under. I had numerous discussions at the show with companies that were at least looking into adding passive sensing into their product portfolio.

Passive RFID Sensing Is Nothing New to the Academic Community

I have been following RFID related research for almost 15 years, first as a researcher myself, lately more through the work of Voyantic’s academic customers. I have also been a member of the technical program committee for the IEEE International Conference on RFID since 2009, which has had me read dozens of scientific papers in the field. Passive sensing seemed to come up more in scientific papers about five years ago. Among localization and energy harvesting, it was one of the topics that I was expecting to transition to the industry at some point.

Passive RFID sensing presents new challenges for manufacturing testing

Typical academic sensor concepts are based on measuring an environmental parameter through changes in an electrical property of a passive RFID tag. I have seen numerous papers on sensing.

  • atmospheric variables such as temperature and pressure
  • mechanical variables such as strain and dislocation
  • chemical parameters such as the presence of different gases and corrosion
  • even the fullness of a beer glass.

However, academic research usually goes only as far as is needed to prove the concept. And that is where all the hard work should start, including proving the ROI of the sensing solution, creating reliable calibration methodology, and manufacturing the sensors cost-effectively.

The sensing solutions that we saw at the RFID Journal Live! are somewhat different from the earlier academic research. In nearly all solutions, the sensor data is read with a regular RFID reader from the memory of the tag IC. The data may be logged into the tag memory with the help of an on-tag battery, or it could be updated at the time of reading the tag.

What Does RFID Sensing Mean for RFID Technology Providers?

For a tag manufacturer, sensor tags present an exciting opportunity to generate value-added products. Sensor tags are more complicated than the most uncomplicated labels, which could allow higher margins. Also, they could allow differentiation from the high-volume, low-cost retail label business. So it is no surprise that a lot of tag manufacturers are looking into the technology.

Passive sensor tags also present some specific design challenges. Of course, sensor tags have to react to the particular environmental parameters in a predictable manner. In addition, the tags should remain readable no matter what the conditions.

Tag design verification should include simultaneous sensor functionality testing and performance testing.

The same holds for manufacturing the tags. Instead of a simple pass/fail testing, sensor tags require testing for functionality and performance. Besides, the sensors may need to be calibrated at the time of manufacture.

Passive RFID sensing presents new challenges for manufacturing testing

So How to Move Forward?

To conclude, the technology for passive sensing is out there. It may not be perfect, but it should be good enough for successful applications. But I guess working in a technology startup for so many years has made me a little cynical towards technology platforms.

Whichever technology is used, it is really up to bringing value to the end solution.

The key drivers in the possible advancement of passive sensing are application developers that are familiar with a specific industry and their problems.

Are you interested in this topic? Download our application note below or (email: text: send me an email), and let’s talk more!

Learn How to Design Passive Sensor Tag

Download our application note “Utilizing Voyantic Tagformance to Speed Up Development of UHF RAIN RFID Sensor Tags” to learn how to design passive sensor tags!

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