RFID: HF versus UHF technologies, Part TwoRFID: HF versus UHF technologies, Part Two
February 3, 2014
Reprinted with permission from: Philips Semiconductors
Compared with ultra-high-frequency (UHF) technology, high-frequency (HF) is far more mature. It has been commercially available since 1995, with the inception of the global ISO/IEC 15693 standards in 1999. Several manufacturers have produced hundreds of millions of HF tags achieving yields of more than 99 percent. The learning curve has been established not only for tag manufacturing, but also for data protocol sharing and the necessary infrastructure to build a Radio Frequency Identification (RFID) application. More than 100 companies supplying chips, inlays, labels, readers, antennas, printers and software currently support the ISO/IEC 15693 standard. Many more companies support proprietary HF products. HF technology has been commercially deployed in markets such as library systems, textile rental and industrial laundry, with an extremely high success rate.
Global standards and power requirements
Government bodies in various regions of the world regulate the bands of the radio-frequency spectrum. The 13.56-mHz HF occupies an International Scientific and Medical (ISM) band, which is available worldwide. With Japan's approval to harmonize the HF frequency in December 2002, the power levels also became the same across the world. Unfortunately, this is not the case with UHF. Standards organizations, such as EPCglobal, Inc., are working with governments to harmonize UHF frequencies. However today, the bandwidth of the frequency, which ranges from 860- to 960 mHz varies from region to region. The U.S. has specified 915 mHz, while the European Union has specific 868 mHz for RFID applications. In one country, the entire UHF band has been allocated to military applications. This variation in frequency allocation requires that manufacturers produce country- or region-specific tags and readers, causing a potential disconnect for companies attempting to create a seamless international supply chain. Japan is just beginning the regulatory process of opening up a viable UHF band for RFID applications. This is true for many other countries in Asia with the exception of China, which has not responded with a standard in the UHF band.
PART ONE OF THIS ARTICLE examines industry pilots, market drivers, advantages of RFID over bar codes, deployment, physics and technology characteristics, packaging and placement for anticounterfeiting protection and much more. Visit www.packagingdigest.com/ info/UHF1
When it comes to power requirements, Europe's ETSI EN 300-220 regulations have two main limitations that make them ?unfriendly? to UHF RFID technologies. The first is a power restriction of 500 mW ERP, and the second is a bandwidth restriction that results in an inability to frequency-hop the reader and also imposes a limitation on the tag anti-collision arbitration speed. The power restriction impairs the achievable reading distance, and the lack of frequency hopping means tag visibility and reading robustness are not optimum. Changes made to the European regulations are expected to permit reader power in the 869-mHz band of 2 watts ERP. Even with this new power level, the continued restriction on signal modulation between the tag and the reader leads to inequality in performance between U.S. and European systems.
Several manufacturers have produced millions of HF tags, achieving a yield of more than 99 percent. More than 100 companies supplying chips, inlays, labels, antennas and more currently support the ISO/IEC15693 standard.
The performance of HF and UHF RFID systems is strongly dependent on the environment in which the communication between the reader and the tag occurs. We discussed the effects of metal and water and touched on the basic physics surrounding electromagnetic interference. HF technology's near-field inductive coupling reduces potential wireless interference issues because no real power is being radiated. Therefore, HF technology has an excellent immunity to environmental noise and electromagnetic interference (EMI). UHF's far-field technology does radiate real power, and its higher signal strength makes it more prone to EMI. In hospital settings, the interference potential of RFID is of high concern. HF technology has been used in hospitals for years and has met the electromagnetic radiation limits of 3V/m, showing no EMI with critical medical devices (see chart).
Consumer privacy issues
Assumptions about what RFID technology can and cannot do are often incorrect or just misunderstood. As with the introduction of any new technology, companies that manufacture and deploy these important tools have an obligation to understand, explain and respond to real and legitimate concerns about the path on which RFID technology may lead.
From a technical perspective, RFID doesn't work like a Global Positioning Systems (GPS) network. Read zones are limited and are not set up to be real-time locators to track tagged items at all times. Most RFID chips today use EEPROM (memory) technology, which allows data to be permanently removed from the chip. Implementation of a disabling feature or a kill command has been specified by standards organizations such as EPCglobal, Inc.
This feature provides the option for the chip to be turned off at point-of-sale, affecting the consumer's ability to take advantage of any after-sale benefits that would require future interactions with the chip. This feature is embedded in all electronic product code (EPC) products and will be incorporated into all of the integrated circuits that are based on EPC standards.
In addition, security encryption methods can be embedded onto the tag to ensure that the data on it can only be read or written specifically by authorized users.
We have an obligation to understand, explain and respond to real and legitimate concerns about the path on which RFID technology may lead.
The creation of encryption specifications for RFID tags created by the standards organizations, now in progress, is a vital step for ensuring widespread protection. Security encryption algorithms have already been established for the 13.56-mHz-based ISO/IEC 14443 standard used for automatic fare collection in public-transit applications.
Report from the field—HF item-level pilots
A number of HF pilots are already underway in the pharmaceutical supply chain and healthcare markets for item-level management. While there is still much to be learned about the efficiencies and safeguards that can result from the use of RFID solutions in these markets, companies implementing RFID pilots are experiencing process improvements and safety benefits today. Suppliers to the medical industry, from garment to surgical instrument providers, as well as healthcare institutions managing blood and tissue-sample processing, are investigating the viability and reliability of HF technology solutions and are seeing significant return in the field.
Surgical garment inventory management
A major medical garment supplier implemented an RFID-based solution to track, trace and manage more than 1 million reusable, class II surgical garments within its supply chain. In order to withstand the intense heat and moisture conditions of the cleaning process, an injection-molded tag was developed and then affixed to the surgical gowns and drapes. Reaching nearly a 100-percent read accuracy, the medical garment supplier significantly improved inventory control, increased quality monitoring and achieved productivity enhancements compared with the traditional bar-code scanning process formerly in place. A substantial short-term ROI was realized and a longer-term ROI is anticipated.
Locating tissue samples
A tissue-sample processing lab is using miniature HF tags to create efficiencies in locating single test-tube samples among the hundreds in the lab at any given time. The HF tag contains a unique serial number, as well as memory, that can be read, modified and protected. The serial number is then linked to a database containing critical information on each tissue sample, including patient data and tissue treatments. Using a fixed-desktop or a lightweight, hand-held reader at a distance of a few inches, researchers and lab technicians searching for a specific sample on a tray of 100 tubes can quickly and easily read all of the tags in less than 3 seconds. What was previously a painstaking and time-consuming task of locating and identifying samples can now be completed quickly with a simple pass of an RFID reader over the existing inventory.
Tracking pathology samples
The Cell and Genetic Therapy Center of the Paoli Calmette Institute in Marseille, France, began a study in June 2003 to determine RFID technology's resistance to precipitous temperature variances for use in tracking biological pathology samples. Working with a group of partners, the center embedded HF tags into the caps of test tubes, which were then immersed in liquid nitrogen and frequently removed during a test period of one year.
After the first year of the pilot, the center found that HF technology withstands liquid nitrogen at a range of extreme temperature variations, from +104 to -321 deg F (40 to 196 deg C), even when temperatures change drastically within only a few seconds. The center's findings demonstrate that RFID technology can be used to track and trace biological samples, even when these samples are subjected to dramatic temperature changes as part of sample processing and storage. Additionally, the results of the study show that researchers in the field using HF technology are in compliance with quality-assurance guidelines such as those recommended by the GBEA and the BPL [guidelines] in France and ISO worldwide.
Matching blood samples to patients
Currently undergoing trials at the Pathology Laboratory of the Portsmouth National Health Service Trust in the U.K., a positive-identification system has shown significant reductions in administration time, both during sampling and laboratory processing. In the trial, the doctor or nurse taking the blood sample enters the patient information into a hand-held RFID device at the start of the blood-sampling process. This data is stored on an HF label on the patient's blood-sample tube and can be read by fixed readers and automatically transferred to the facility's database, enabling a fully automated process and replacing an entirely manual one.
By reducing errors and allowing faster processing of samples, costs are reduced and patients have access to their results more quickly. In addition, because the patient data is entered in electronic format at the beginning of the process, integration of results into the patients' records is quick and simple.
Patient identification and care
The U.S. Navy is using HF technology to more efficiently track the status and location of hundreds of wounded soldiers and airmen, prisoners of war, refugees and others arriving for treatment at Fleet Hospital Three, a 9-acre, 116-bed facility in Southern Iraq. ScenPro's Tactical Medical Coordination System (TacMedCS) allows medical professionals to use RFID-enabled wristbands from Precision Dynamics Corp (www.pdcorp.com) to identify patients and to update their status, location and medical information in the system's electronic whiteboard automatically.
The Navy implemented TacMedCS to replace a labor-intensive, entirely manual system consisting of pen and paper, paperboard tags and a centrally located whiteboard to show patient movement throughout the hospital. With the new electronic system, each patient receives an HF-enabled wristband on which basic identification information is stored. Medical professionals use a hand-held RFID device to read the unique identification number and to add or change data to create a digital treatment record that travels with the patient as he or she is moved throughout the facility. Using a wireless LAN, they transfer patient information to an electronic patient-management system, further eliminating manual re-entering of data at a central computer terminal.
Precision Dynamics and Georgetown University Hospital's (GUH) Blood Bank began a pilot study on March 1, 2004, to explore how RFID wristband solutions increase the efficiency and reliability of blood-transfusion safety.
For more than two years, GUH's Outpatient Infusion Service has used a bar-code solution as standard practice for double-checking and verifying blood transfusions. GUH is interested in learning whether RFID solutions can increase the efficiency and reliability of transfusion safety in instances where a bar-code ID isn't as effective.
To ensure positive patient identification, the RFID wristband acts as a portable, dynamic database that carries patient information to be used and updated during a patient's stay. This accurate, automated system ensures the integrity of information between patient, host device and hospital-information system.
Hospital item management
Designed for use in operating rooms and catheter labs, as well as for radiology, orthopedics, neuroradiology and cardiology departments, Mobile Aspects' (www.mobileaspects.com) HF-based inventory system has been implemented at four of the top 15 U.S. hospitals. The system automatically manages equipment and supply inventory, allowing for real-time reports to be generated as supplies are removed from RFID-enabled cabinets, and for integration with the hospital's information systems to facilitate seamless item replenishment.
Supplies are tagged with HF inlays and the cabinet compartments contain RFID readers. Once an item is removed from the cabinet, the software requests a scan of the existing inventory, identifying all remaining items and noting which item was removed, by which particular staff person, and at what time. RFID allows this to occur automatically, without manual reading of bar codes, increasing productivity, enhancing the quality of care, reducing costs and simplifying the overall process.
With its installations, Mobile Aspects has proven a less-than-one-year return on investment (ROI)—a significant improvement on the typical two- to three-year payback for hospital inventory-management technologies.
The promise of a safer, more accountable and highly efficient supply chain, combined with the U.S. Food & Drug Administration's support for the technology, is driving interest and demand for RFID in the pharmaceutical industry. Manufacturers, distributors and retailers are poised to take advantage of the technology's many benefits and are in the midst of conducting pilots to better understand and apply the technology to their businesses. When it comes to the choice of frequency, each has its advantages. Due to a number of technical and deployment characteristics, including read range, form factor, maturity, global standards and worldwide availability, HF technology provides the most effective path with the lowest technical and business risk to achieving item-level identification and pedigree tracking for pharmaceutical and healthcare applications.
You May Also Like