Impinj Releases Compact High-Performance EPC RFID Portal

By Claire Swedberg

Apr. 6, 2010—Impinj, a provider of passive ultrahigh-frequency (UHF) RFID technology, has unveiled a new UHF EPC Gen 2 interrogator, the Speedway xPortal, as well as a new reader antenna, the Dual-Linear Phased Array (DLPA). The xPortal, which includes an integrated DLPA antenna, is designed to be smaller and less expensive to install and operate than existing portal readers, which are used in doorways and other portals through which tagged items or individuals with ID badges pass. The company claims the xPortal will save users an average of $1,000 per doorway, requiring no AC power cabling and being less expensive to ship. What's more, Impinj reports, the device offers a high read rate.

The Speedway xPortal

According to Impinj, the system is intended to offer customers a solution to existing problems with portal readers. Currently, there are two options for portal readers, says Scot Stelter Sr., the firm's senior director of product marketing. The first is a floor-mounted steel cabinet-housed reader that can weigh 150 to 200 pounds, be unattractive and difficult to install, and require considerable energy to operate. That option also takes up considerable space, and is thus unrealistic in narrow passageways, such as some hallways that connect a retailer's storeroom to its sales floor. The other option is a "do-it-yourself" installation, Stelter says. In that case, an end user mounts readers and runs the cable necessary to power them, in addition to a local area network (LAN) connection. That type of installation, he says, "is messy and more expensive, because there is labor involved," such as a licensed electrician running the power cable.

The xPortal weighs 10 pounds, stands approximately two and a half feet tall and measures 8 inches wide by 2 inches deep. The device is designed to have a low profile while maintaining high performance, says Daniel Bowman, Impinj's senior marketing manager. The design of the antenna and reader itself allows the xPortal to consume less than 13 watts, he says, enabling it to be powered over Ethernet. This means an Ethernet cable is all that needs to be installed with the reader. Traditional portal readers draw 25 to 40 watts, Stelter notes. And while there are other interrogators that can be powered over Ethernet, he adds, the performance (read rate) is not as high as that offered by the xPortal. That read rate varies, though, he says, according to the environment and the items being tagged, it is in the very high 90th percentile. "In testing at a pilot retail customer," Stelter says, "using the xPortal improved read reliability 1 to 13 percent, depending on the product [being tagged], versus a standard Speedway Revolution reader with off-the-shelf far-field antennas in traditional steel portal stands."

Daniel Bowman, Impinj's senior marketing manager

To accomplish this high read rate, Impinj has deployed several of its own technology innovations. A portal, Stelter says, paints a narrow curtain of RF transmission. The Dual-Linear Phased Array, which consists of a pair of linearly polarized antennas that constantly switch from horizontal to vertical transmissions, gives the xPortal the ability to read tags despite their orientation. Typically, linear antennas must be configured to correspond with the expected orientation of the antennas within the tags passing through a portal. Another option is a circular antenna, which can capture reads from tags at any orientation, but the energy is distributed throughout that circular form, making it somewhat less efficient—and, therefore, providing a shorter read range—than linear antennas. With the DLPA, Stelter explains, the reader antennas offer the efficiency of linear antennas but the reliability of circular antennas. (Another RFID vendor that sells an interrogator that employs phased-array antennas is Mojix.)