RFID Reader
RFID readers transmit RF signals that cause compatible tags to emit return signals. The tag’s information—a unique electronic identity, managing organization, asset description, and serial number—is encoded in the signal.
COTS readers operate on a frequency-hopping basis to mitigate co-channel interference and frequency selective fading. This hopping causes phase values to change discontinuously every 0.2 s.
Power
A radio frequency identification reader is a network-connected device that uses a scanning antenna and a transceiver to read RFID tags. It transmits a radio wave to activate the tag, then receives a return signal back from it with information about the tagged item. This information is translated into RFID Reader data by the reader, which can be fixed or portable and connected to a laptop or server.
The size of an RFID chip determines how far it can communicate with a reader. The most common sizes are a few millimeters wide, but newer chips can be a fraction of that size. This allows for more tags to fit on a single board and shrinks the cost of the system.
As the technology evolves, RFID tags can also have more sensors built in. This allows for more advanced applications such as monitoring the temperature of a perishable product. The tags can also be programmed to respond differently to readers, depending on their application. For example, some retailers add RFID tags to clothing so they can detect when an employee steals a garment and send an alert to store security.
Every organization that needs to automate the tracking of items and share product-specific information in near real-time can benefit from RFID systems. To learn more about the latest innovations and applications, register to attend this year’s RFID Journal LIVE! event in Phoenix on Sept. 26-28.
Antenna
The antenna of an RFID reader transmits Radio Frequency (RF) signals that are picked up by a tag attached to an item. When the RF signal is absorbed by the tag, it power up its embedded chip and return data to the reader. The data is captured by the reader’s antenna and decoded to form a digital signal that is sent to a connected system.
The design of the antenna can impact the reading range of an RFID system. For example, circular polarized antennas can desfire ev1 read tags from a wider area than linear polarized or even non-circular polarized. The type of RF identification tag used can also impact read ranges. Passive RFID tags can operate at higher frequencies, but are prone to interference by liquids and metals. Active tags use a battery for power, allowing them to operate at a much greater distance from the reader.
Some RFID readers include a built-in antenna so that the device is smaller and easier to install. This option is ideal for handhelds that are often used in retail for picking and order fulfillment. However, external antennas are available for RFID readers that need to be placed in a fixed location or mounted on a mobile vehicle. In addition, panel antennas can be placed in a defined zone of coverage such as a warehouse bay to scan all items that pass through it.
Cable Length
The longer the cable between the reader and the antenna, the more power is lost along its length. This loss will decrease your RFID tag read range and can sometimes degrade the performance of the reader to the point of being unable to detect tags or providing inaccurate data. To combat this, it’s a good idea to use high-quality cable with a higher rated insulation.
SkyRFID offers low-loss LMR 240 and LMR 400 UV resistant polyethylene jacketed cables at competitive prices. We also stock a wide variety of connector types (Male N end cable connector for most Gen 2 readers, RP-TNC Female on many Reader End Connectors and RP-SMA Male for other cable to Reader connections) to ensure that you can get the right cable for your installation.
The cable length of a reader can be determined by following the path where you want to install it and measuring the distance from the Reader End Connector to the Antenna connectors with a soft measuring tape or string. The measurement should be made to the exact cable length, as any deviation can have a significant impact on your RFID reader’s ability to detect tags and provide accurate data. For example, if you are going from a two foot cable to a thirty-three foot one, that can dramatically decrease your read range.
Frequency
RFID readers transmit radio frequency (RF) signals to activate tags attached to items. The RF energy is absorbed by the tag’s embedded circuit and antenna, triggering it to “wake up” and transmit data back to the reader. The data is decoded and sent to a connected system, such as a database. The entire process is automated, eliminating the need for manual intervention, which reduces labor costs and increases accuracy.
Most RFID tags include an embedded chip that stores a unique identification number, as well as other information such as an Electronic Product Code (EPC) or barcode. Using radio waves, RFID tags and readers communicate over short ranges. Tags can be either active or passive, with the latter relying on an integrated battery to operate their circuit and antenna. Both types use the RF energy received from the RFID reader to “wake up” and transmit data.
RF frequencies used by RFID tags and readers vary depending on the region where they are being deployed. For example, a COTS RFID reader will hop among different channels as it communicates with tags in the United States to mitigate frequency selective fading and to comply with radio-frequency (RF) regulations. This hopping causes the captured phase data to change with each channel change, creating a discontinuity in the measured phase values.
To address this issue, RFID readers often come with software development kits that include sample programs and API access to enable a developer to begin developing their own custom applications or integrate the reader into an existing system. The kit may also include a variety of antennas so that the user can create a specific area for reading, such as an entire warehouse bay.