Jan 04, 2006In a benchmarking test of passive RFID tags compliant with EPCglobal's UHF Gen 2 Class 1 standards, all 11 tag models tested reportedly showed improved performance over EPCglobal's previous Gen 1 standards. Tags made by Alien Technology, Impinj and RF IDentics, meanwhile, "distinguished themselves in a number of tests," according to Bret Kinsella, vice president of operations and marketing for ODIN Technologies. The Dulles, Va., RFID systems integrator conducted the tests and the benchmarking project was sponsored and partially funded by global technology services company Unisys.
Kinsella notes that when the 11 tag models were interrogated at short distances, facing the interrogator, they performed equally well. Variances in performance crept in, however, as the tags were brought farther from the interrogators, when they were orientated away from the interrogators and when metal objects or water (both well-known sources of RF interference) were nearby.
Size mattered, as well. The larger a tag's antenna, the more likely an interrogator could read the tag—but the differences in read rate between a large-antenna tag and a small-antenna tag were not always dramatic. While Impinj's Banjo tag performed well, Kinsella says, it is larger than Alien's Squiggle model, and RF IDentics' Micro, Mid and Flex models all showed strong performance despite their smaller size. "Symbol's Trident tag and Texas Instruments' TI Gen 2 tag also fared well across a number of categories despite a modest size," he says.
The other tags tested were Avery Dennison's Strip tag, Impinj's Propeller tag and UPM Rafsec's Short Dipole and Pharma tags. The criteria ODIN used in selecting the models to test were that they be available in lots of 5,000 or more, and that the manufacturers be willing to sell ODIN 100 individual samples of the tag for the tests. The company tested these 100 samples of each in order to address variations in production quality. All tag models selected for testing were designed to meet the RF regulatory requirements of the United States, not those of Europe or Asia.
Each tag was put through five separate tests, which measured the strength of the RF link (the tag's ability to extract and consume an RF signal from the interrogator and then reflect it back to the interrogator), how the strength of this link changed as the distance between the tag and interrogator grew, how the orientation of the tag to the interrogator's RF signal affected the tag being successfully read, and how nearby materials (such as metal and conductive liquids) affected read rates. Using a spectrum analyzer, ODIN also studied the unique spectral signature of each tag. Kinsella says this test can provide insight into tag communication efficiency beyond what the test measuring RF link strength reveals. "Tag communication efficiency and the power of the backscatter [the tag's ability to reflect the RF signal back the interrogator antenna] is directly related to tag read performance," he explains.
Odin has published the full results of its tests, along with insights into criteria end users should use when making decisions about tag selection, placement on cases or pallets of product to be tagged and tag orientation. The report, titled "RFID Gen 2 Tag Benchmark," is available at ODIN's online store. A single-user license costs $750, while an enterprise license costs $1,500.
This is the fourth benchmarking analysis of RFID hardware ODIN has released since June of 2004. The company previously studied the performance of EPC UHF Gen 1 Class 1 tags (see ODIN Benchmarks RFID EPC Tags), as well as the fixed-position and mobile interrogators designed to read them (see ODIN Benchmarks RFID Readers and ODIN Benchmarks Handheld Readers).
