Harting’s LocField Reader Antenna Promises Flexible Read Range

By Claire Swedberg

The antenna—in the form of a coax cable bendable into any shape—could be installed along a shelf or rack, within a vehicle, or around a machine's interior, to create a precise read zone.

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Systems integration customers of Harting Technology Group’s RFID division are testing a new ultrahigh-frequency (UHF) RFID antenna in the form of a flexible cable up to 10 meters (32.8 feet) in length that can read passive EPC Gen 2 transponders located up to 7 feet away in any direction. Harting’s Ha-VIS LocField antenna can be installed as a straight line extending from a reader, or it can be bent, enabling a read zone to be extended further than would be possible using a conventional patch antenna. (The name LocField is derived from the words “localized field.”) Users of the new antenna would be able deploy UHF readers in a variety of configurations and achieve functionality close to that of a real-time location system (RTLS), explains Jan Regtmeier, Harting’s product team manager. The Ha-VIS LocField is expected to be made commercially available in Europe and North American next month, and later in other parts of the world, such as Asia.

Harting provides technology used to solve problems for automotive suppliers and other businesses, in such areas of mechanical engineering, rail systems, wind energy plants, telecommunications and factory automation. Its RFID division offers EPC Gen 2 UHF readers and transponders for managing assets and inventory in these sectors. Many of Harting’s customers seek asset-management solutions for their data centers. However, Regtmeier says, most RFID systems are not feasible for such applications, since they would require an unrealistically large number of antennas to provide the kind of real-time visibility many data-center managers want. Instead, he adds, most companies still track their servers and other IT equipment manually, via pen and paper or bar-code scanners, assigning employees to walk down aisles and identify which equipment is located at which location—a very time-consuming task that is thus not undertaken very often. Those using RFID are gaining some benefit, he says, but in most cases, the technology requires that workers carry handheld readers and walk through aisles capturing tag data in order to gain visibility into what is on the racks at any given time.

The Ha-VIS LocField UHF reader antenna

Harting has been working to create a solution for these customers for several years, Regtmeier says. In 2013, the company developed the Ha-VIS LocField, a traveling wave RFID antenna consisting of a coax cable that—when plugged into the antenna port of a UHF Gen 2 reader (either a Harting model or that of another vendor)—conveys the reader’s RF signal along the cable’s copper core and to the antenna’s far end, where a coupling element draws the RF wave out and onto the cable’s exterior. When that signal reaches the reader, a metal protecting shield prevents the interrogator from receiving its own signal and interfering with its performance.

If used with a high-powered reader (such as Harting’s Ha-VIS RF-R500 Long Range Reader) transmitting a signal with 4 watts (36dBm) of what is called effective isotropic radiated power (EIRP), a version of the LocField antenna measuring 10 meters (32.8 feet) long and 5 millimeters (0.2 inch) in diameter would have a read range of 6 to 7 feet in radius along the cable’s entire length. A reader with two ports could be connected to two LocField antennas, and if each were extended to 10 meters, they would provide a coverage area with a total length of 20 meters (65.6 feet). The antenna is flexible so that it can be run around corners and up and down racks, or be bent to accommodate other space demands. The company has also designed a version of the antenna 3 millimeters (0.12 inch) in diameter, offering a maximum read radius of 3 to 4 feet.

To achieve the same read range provided by a LocField antenna, Regtmeier says, users would need to install multiple patch antennas, each with its own cable. In a typical data center, he notes, a single reader with two LocField antennas could interrogate tags throughout approximately four racks, while a conventional deployment would require four patch antennas or more to provide equivalent coverage.

Harting began building prototypes of the LocField antenna this year, and has sent the technology to about 10 systems integrators throughout Europe and North America, which are currently testing the technology to determine how it might benefit their customers. Some are testing the LocField-based solutions at data centers, he says, while others have found different use cases.

Many of the integrators, Regtmeier reports, have been requesting an increasing number of the prototype LocField antennas to test in a wide variety of settings. “The systems integrators are keen on getting as many antennas as they can get,” he says.

According to Regtmeier, at least three of the systems integrators are exploring how the technology could be used to track equipment loaded inside vehicles. In the case of a vehicle filled with tools, for example, a single RFID reader with patch antennas might not be able to interrogate all UHF tags within that vehicle, whereas installing a LocField antenna running throughout the vehicle could resolve that problem. Several systems integrators are also testing the antennas for use in retailer smart-shelf applications, while two are considering utilizing the antennas in manufacturing equipment, such as inside injection molding or packaging machines containing dozens of distinct modules that are inserted or removed based on the specific function the machine is providing for a particular order. In this scenario, the modules could be tagged with UHF RFID tags, and the antenna would be used with a reader to identify all modules within that machine.

Harting’s Jan Regtmeier

At present, Regtmeier says, the technology is being tested by systems integrators in Germany, the United Kingdom, parts of Eastern Europe and the United States. He expects LocField antennas will be sold worldwide once testing is completed later this summer, he adds.

“Our next step,” Regtmeier states, “is to see if the customers are satisfied with the antenna. So far, we’ve been seeing excellent reading results.” Many of the systems integrators have asked about customizing the antenna’s length, which Harting can accommodate. For example, some may need a 15- or 20-foot version for a specific use case. The read distance depends on the reader’s power, he explains. A reader transmitting a signal at 2 watts EIRP would provide a read range with a radius of 3 to 4 feet encircling the antenna, while a 4-watt reader would be able to double that read range.

The LocField antennas will be priced at about $275 to $400 apiece, Regtmeier says, depending on their length and diameter.