The European EPC Competence Center (EECC) has completed its latest annual UHF RFID chip survey, which finds that chips are gaining intelligence that could have implications for the furthering of affordable Internet of Things (IoT) adoption. Of the 400-plus UHF RFID chips being tested by the group, some offer functionality that takes tags from simply passive identifiers to intelligent devices that could sense conditions around them, tailor responses based on conditions or circumstance, and issue alerts based on environmental changes.
In addition to bringing functionality such as untraceable commands and other functions related to when and how RFID tags respond to interrogation, the survey also found that UHF chips have improved their sensitivity by about 20 percent over the previous year. The study, known as “UHF RFID Transponder Benchmark (UTPS) 2018-2019,” has grown in scope from 20 UHF RFID chips tested in 2007 to more than 400 for the current survey. The EECC calls it the worlds’ most comprehensive transponder benchmark in the world (see European EPC Competence Center Releases UHF Tag Study and EECC Benchmark Study Finds UHF Tag Performance Better Than Ever).
The study consisted of 25 different measurements in the 800 to 1,000 MHz frequency range for each tag. For example, each tag’s read range was measured at different rotating angles, with steps of 7.5 degrees, and both forward and backward radiated signals were measured as well. The tags were also applied to different materials covering a large spectrum of dielectric constants commonly found on RFID applications, and another test measured backscatter tag responses. Write speed, on-metal performance, close proximity reading and interference rejection were measured as well, says Mauricio V. León, the EECC’s technical and implementation manager.
To qualify for testing, every chip needed to be commercially available in a tag and relevant to the market. The EECC says it requested tags from all major commercially available RFID tag manufacturers. According to Conrad von Bonin, the EECC’s CEO, since the 2017-2018 survey, four chips newly produced in commercially available tags were among those tested: Alien Technology‘s Higgs-EC, NXP Semiconductors‘ UCODE 8 and UCODE DNA, and Impinj‘s Monza R.
Since the latest survey began, the EECC has seen the RFID industry transition through multiple phases, von Bonin says. In the first step of UHF RFID’s evolution, he explains, “RFID simply made all things identifiable with a unique ID. Today, we can tag most objects on the market.” What’s more, the cost of tags has dropped to between about 5 and 10 cents. About three years ago, he adds, passive EPC UHF RFID tags entered a new phase with the addition of temperature and humidity detection built into the chip. “This allowed us, for the first time, to collect dynamic information about the status of the tag,” von Bonin says, without requiring separate sensors or batteries.
The third step for UHF RFID, according to von Bonin, is now under way—namely, providing controllable communication. For example, an untraceable command allows users to set their tags to hide part of their memory. The latest technology, such as that featured in UCODE chips, can enable each chip to respond with only part of its ID number, based on who is interrogating it, or when or where it is being read. The data transmitted could be isolated to the ID for a particular manufacturer or country of origin, or it could be the entire ID number.
Additionally, the UCODE DNA is capable of controlling how loud its tag responses are. They can be set to “shout” (with a nominal read range) or to whisper (with a reduced read range), according to a user’s specific needs. That feature enables privacy settings so that, for instance, RFID tag reads cannot be captured from a distance on a tag attached to a purchased garment. However, if the garment were returned to a store, retailers could still read the tag’s ID with a reader in close proximity.
Another scenario León cites is a crowded, noisy environment in which many tags are being interrogated—for example, as they move through a portal at a dock door. In this case, some tags may be responding to interrogation with a signal that drowns out the less sensitive tags. The toggling functionality in the new chips would then instruct already inventoried tags to lower their voices so that all tags can be detected at once.
Von Bonin sees the fourth step in the evolution of UHF RFID on the horizon as well. This, he says, will involve the intelligence of tags—the ability for them to make decisions based on data, such as detecting a temperature rise and then transmitting an alert indicating as much the next time the tag is read.
Von Bonin cites the analogy of a cup of tea, noting that tracking the conditions of a single hot beverage would be unrealistic with the high cost of most IoT sensor-based technologies. But with a low-cost UHF RFID tag, it becomes possible if there is sufficient sensitivity and low enough power requirements to capture and forward sensor data with a UHF chip. So, for instance, a cup’s tag could identify if the tea were too hot or cold, then transmit that information to an interrogator. This could also work with other perishables, such as a frozen pizza coming within proximity of something warm, (a cup of tea, for example), or simply being left out of the freezer. In the former scenario, the interrogator could capture and combine the temperature of one object (the pizza) with the proximity to another (the hot tea, based on its tag location) and could trigger an alert to the system.
Von Bonin imagines a time might come, with passive UHF chip development, when tags will be able to transmit this kind of data to an interrogator, or to each other. For instance, engineers at Stanford University and the University of California, Berkeley, built a radio in 2014 that was about the size of an ant. The radio was so energy-efficient that it could use the interrogating energy it received to send a signal not only back to the reader, but also to other tags in the area (see Stanford engineers aim to connect the world with ant-sized radios). A lot of this functionality will be provided by the increasing sensitivity of UHF RFID chips, León says, and by their ability to operate at very low energy.
The EECC updated its own measurement tools to ensure it could test the latest chips to their fullest capacity, including the untraceable command. That new equipment was provided by Austria’s CISC Semiconductor. “We were very excited to see that these features really work,” León states. “We have tested and verified that the chips work as we expected.”
The long-term opportunities are exciting, León says. “We are enthusiastic that this might be a door to a new, wide playground” in which new information can be captured and then managed with very low-cost UHF passive RFID tags. At EECC’s Innovation Labs, for instance, researchers already have demonstrated how passive UHF RFID tags with sensing capabilities can detect of a computer hard-drive becomes too hot—and in the future, León says, if a tool were to fall on the floor, its tag might be able to transmit that event based on sensor data.
In the meantime, the survey is designed to help end users and technology developers identify the proper UHF tags for specific applications. That becomes a more complex decision as more RFID chips enter the market each year, von Bonin notes. If a company has already been using RFID technology for several years, the latest, most sensitive tags might not be a good choice. The survey details are intended to help those RFID users and providers identify the best product for existing and planned RFID systems.
Each year, León says, the EECC asks every RFID chip producer to send its newest products for testing. The latest functionality of recently released RFID chips is now being tested in multiple pilots, von Bonin reports. The study is available for purchase at the EECC’s website. In addition to conducting research, the organization consults with companies developing their own UHF RFID-based solutions.