Category: Industry Insights

中文版 Chinese version

Electronic Vehicle Identification (EVI) is a perfect match for RAIN RFID (UHF RFID) technology. Once a vehicle is tagged, the possibility to identify the vehicle remotely enables a lot of applications and services. While vehicle tagging is of high interest, it is not the easiest task. In the past few months I have worked with some vehicle tagging projects and learned that the application requires some special attention from technology providers.

EVI Tag Types

The EVI tags come in different forms. Most common EVI tag types are

• windshield tags attached to the windshield inside the car; and
• license plate tags mounted on license plates outside the vehicle.

There are some specific design issues related to both of these tag types.

License plate tags must be on-metal tags, and very durable. They must survive weather conditions and car washing. Also, the position and the mounting angle are rarely ideal for readers. The natural best reading direction is straight backward (or forward), and at low height. In many applications the goal is to identify a vehicle approaching an identification point, for example an access gate or a road toll collection point. Reading would preferably be done from above or from side with an angle.

Windshield tags provide better reading angle. The challenge is to design a tag that works well with all possible windshields, regardless of the windshield’s angle, thickness, material, embedded technologies and type and proximity of the windshield frame to the tag position.

Both passive and semi-passive tags are commonly used. The semi-passive tags are battery powered; more of those can be read in earlier Voyantic Blog post.

EVI Tag Applications

Once the tagging is successful, it is easy to find use for the tags. Applications include road toll collection, tracking vehicle registrations and inspections, tracking tax payments, and parking control. Many of the applications are initially set for government purposes. Once the tags are in place, they can also be used in various value added applications of the private sector. Even if the tag is initially placed for registration, it can be used as a parking permit and gate access permit of a housing community.

Performance Testing of EVI Tags

A car is a special case of a tagged item. There are components that reflect RFID signals, absorb or block the signals, and may even resonate with RFID frequencies. These effects are different to different reading angles, they vary when a tag is attached to different position in a vehicle, and may even change when a tag’s mounting orientation changes. At Voyantic we have assisted several companies in defining test methods and processes for optimizing the EVI tag performance.

With the Voyantic Tagformance Pro system it is possible to test the sensitivity, tuning and backscatter signal strength of the car tag. The Tagformance system is an essential tool for evaluating effects of reading angles and mounting positions. The system can also be used for optimizing the EVI tag performance, finding optimal tag positions in the cars, and for finding optimal reader antenna positions for the applications.

Learn How to Test EVI Tags with Tagformance Pro

Download our application note to learn how to avoid the pitfalls of EVI tag testing!

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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.

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.

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.

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.

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.

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.

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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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.

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.

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.

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!

When selling RAIN RFID tags: wouldn’t it be great to prove that the proposed tag is the best possible one for the customer’s application instead of just sending out loads of free samples hoping that the customer tests them properly? And when purchasing: wouldn’t it be great to have comparable data of how each tag works in your application instead of “our tags are the best ones, you can trust us” statements?

Guess what: it is possible, and in most cases, the salesperson or the buyer just needs to know what to ask. Tag developers have a lot of characterization data ready. Read on to see how to leverage that data following the 3-step approach!

Step 1: Extract Tag Characterization Data from the Production Quality Log

Useful RAIN RFID tag data combines production quality information with detailed laboratory test results. Production quality data is a good starting point since it shows the overall quality variation. With Voyantic’s Sweep Data Analyzer, it is easy to identify the typical and the worst acceptable tag and to quantify variation. Variation can be described, for example, as each tag having a sensitivity of -8 dBm +/-2.5 dB. With the Tagformance viewer software, the sensitivity values can also be translated into read ranges.

Step 2: Connect RAIN RFID Tag Performance Data to the Use Case

Detailed information about the performance of a RAIN RFID tag can be generated by testing the selected sample tag (typical tag or weakest tag) in a laboratory environment. The goal of the laboratory tests is to show how the tag would perform in different applications. Simply place the tag or tags on Voyantic Reference Materials in different arrangements and run the tests on Tagformance.

When proper test data is available, there is no need for extensive field tests with various tag and reader combinations. Shortening the field tests saves time and money significantly – both for the seller and the buyer.

Typical test results include RAIN RFID read ranges and orientation patterns on various materials and within diverse tag populations. When the tags are attached to different materials, their tuning, and performance level change, with the test results, it is possible to evaluate what the read range would be with varying models of readers. The results predict how the real-life RAIN RFID system will work. With proper tag data, even RAIN RFID readers can be easily compared, and the bottleneck of the system performance can be identified.

Step 3: Let the Customer Play with the Data

Utilizing RAIN RFID tag test data is really simple. As a result, you are able to assist your customer efficiently, and most likely, also to shorten tag sales cycles. If you want to learn the specifics related to RAIN RFID tag data crunching utilizing the Tagformance software, please read on.

Tagformance Read Range test results are an excellent way to compare tags. Choose test data with the tag population and material corresponding to the RAIN system use, and enter reader the information.

The graphs show the read range of one RAIN RFID tag with two different readers.

When the tag is tested with the RAIN RFID reader parameters entered into the system, the test results show the overall system performance.

In the first case, the system level read range bottleneck is tag sensitivity, and the resulting read range is 8 meters (26 feet) in the FCC frequency range.

In the second scenario, the reader has lower sensitivity, read range decreases to 5 meters (16 feet), and the system level bottleneck is reader sensitivity.

It is also easy to tie production variation to the test results. With production, variation included the read range variation is 3.5 meters to 7 meters (12 feet to 23 feet).

Producing the same information with tag samples and a reader is difficult and uncertain. Depending on the selected sample tag, the expected read range may be anything between 12 feet and 23 feet, and there is no information about the variation. Surprises await in implementation, and counting accuracy is likely to be well below 100%.

Other test results show, for example, the orientation pattern – how the read range changes when the tag and the reader are not facing each other directly, and how the tag performance changes when there are multiple tags in front of the reader.

Good RAIN RFID Tag Performance Data is a Powerful Sales Tool

There is a lot of tag test data available, and the Tagformance viewer software is an excellent tool for presenting the data to the customers.

Tagformance Viewer is Available and Can Be Used by Anyone

With the viewer software, it is easy to choose results from RAIN RFID tag tests corresponding with the customer’s intended use scenario, input reader information, and see the actual system-level performance.

Download a Sample Datasheet Showing RAIN RFID Tag Performance and Quality Information

Download here an excerpt from a sample datasheet showing how to tag data could be presented in a datasheet. The sample shows how the tag performance and quality information is presented in a format that is useful for the customer in tag selection.

Download Sample Test Data and Tagformance Viewer Software

The Tagformance viewer software can be used to view test data. By inputting different reader parameters, such as reader power, to the software, the application shows how the read range changes. By inputting tag variation information, read range variation can be seen. The viewer software can be used for viewing and analyzing data from the tag developers and manufacturers. Would you like to try? Contact us and I will be happy to send you the software installer with demo results!