BY KEN HORTON

Radio frequency identification technology has been embraced by a growing number of industries to improve the quality and timeliness of data used for asset management. RFID systems collect data automatically, freeing up time, labor and capital resources and reducing costs. Businesses need high read rates from RFID tags to ensure the accuracy of their data. Selecting the right tag—standard or custom—is critical to the proper functionality of an RFID system.

While a standard, off-the-shelf tag works well for many applications, there are circumstances under which a standard tag falls short. When optimizing performance becomes tricky or impossible with a standard tag, it is worth considering a custom tag to improve an RFID system's performance. There are several factors that may make it difficult for a standard tag to meet the requirements of a given business process. Here are some of the most critical factors that might dictate the need for specially designed tags.

Environmental Materials

The materials on which a tag is mounted, the materials surrounding it and any materials that may be moving around the tag during the business process all impact how well a reader will pick up its signals. A tag designed to compensate for or take advantage of these environmental factors can often out-perform a standard tag designed without such considerations.

The factor that most often impacts the performance of RFID systems is the amount of metal in the tag's environment. Tags that will be mounted on or near metal must be properly designed to work on a conductive substrate. Clever engineering can improve the read range of tags mounted on metal or other conductive surfaces.

RFID energy cannot pass through metal, so tags can be missed if they are positioned in the shadow of a nearby metal object. On the other hand, metal reflects some RFID energy, and a tag design can take advantage of these reflected signals. Other materials that can affect tag performance are fluids, both liquid and in the form of high moisture content in wood or other hydrophilic materials. Proper tag design can compensate for these material-related effects and ensure good read rates even in these challenging environments.

Durability

Standard tags are designed for applications that place standard duress on the tag. Most RFID tags are designed for the benign conditions of an office, retail or warehouse setting. They cannot tolerate much exposure to moisture, high heat levels or sub-freezing temperatures. Other tags are designed for outdoor use. They can handle the rigors of exposure to any sort of weather conditions, from the moisture and cold of an arctic expedition to a desert safari.

Yet another level of durability applies to tags that can withstand the extreme conditions of industrial processes like paint-curing chambers, autoclave sterilization or cryogenic storage. If an asset being managed is subject to extreme conditions, a tag tailored to tolerate these conditions will be needed.

Stressors that a custom tag can be designed to tolerate include extremely high or low temperatures, very acidic or basic chemistries, high or low pressures, high vibration and extended immersion in fluids. A medical device manufacturer's analytical product that is subject to high-temperature environments makes a custom tag the right solution to achieve durability. Over-the-road vehicles exposed to road salt and freezing temperatures require another type of durability. There are many applications for which an off-the-shelf tag may not have the right set of durability attributes for a particular use case.

The Right Fit

Another factor that motivates customers to develop special tags is geometric constraints. Some devices have limited space in which to mount a tag, or the space has an unusual shape. In other cases, the tag must fit around or into another device whose geometry is not compatible with the square or rectangular shape of most standard tags. A designed-to-specification tag can often solve tagging problems that are driven by the geometric constraints associated with the item being tagged. For example, doughnut-shaped tags are called for to fit around cylindrical parts. Tags can also be designed to fit into cavities in other parts.

Cost Considerations

Every application has cost constraints, and sometimes a standard tag will not meet those constraints. With a designed-to-purpose tag, it is often possible to strip out the features of a standard tag that are not needed for the customer's application, but which add significant cost.

Features of standard tags that add cost but do not always provide benefit to the user include holes for bolt or screw mounting, a plastic cover or encasement, and an expensive construction material for which another material can be substituted. With a clean sheet of paper, the designer can focus on delivering the RF performance needed by the application without features or materials of construction that are not needed, and can reduce the cost of the solution by providing only the needed feature set.

Engineering for the Application

Developing a specially designed tag starts with clear objectives and requirements, including timeline, cost, geometry and the environment of the business process in which the tag will be used. Once the requirements are clearly understood, the designer can determine whether an existing tag design can be adapted to the use case—an option that is lower-risk, lower-cost and shorter-cycle—or if a completely new design is required. The RF performance of the new design will be modeled and simulated electronically. Then a prototype design will be created, and materials for construction of prototypes will be assembled. Modeling is rarely perfect, so several variations of the tag will be built so the best design for the application can be determined experimentally in the real world.

Tags are tested in standard conditions for baseline performance and then in conditions simulating ways in which they will be used. Through an iterative process, the design that best meets the requirements is selected for use in a pilot run or full production. The process for creating an application-specific tag is more complex and costly than selecting an off-the-shelf tag. However, there are business processes for which standard tags will not work, others in which they provide poor performance and yet others for which they are too costly. Tailored tags can provide benefits in terms of performance, durability and cost, which will result in an RFID system that provides a superior ROI.

Ken Horton is the CEO and cofounder of Vizinex. He focuses his time on sales and marketing and also being the CFO. Ken has worked in the RFID field since 2008, in operations roles as well as in sales and marketing. Prior to the founding of Vizinex, he served in executive positions in several small high-technology firms. His experience includes leadership positions in operations, engineering, and sales and marketing. For 25 years, his industry experience has included medical instruments, automated electronic assembly equipment, PC-related hardware and software products, and semi-conductor production equipment. Ken has an engineering sciences degree from Dartmouth College and an MBA from Stanford University, and he is a graduate of General Electric's two-year Manufacturing Management Program.