RFID Readers and Antennas
RFID Readers and Antennas
RFID readers send RF energy to tagged items to read their data. They amplify the signal, modulate it with information, and transmit it via an antenna cable to connected RFID antennas.
The resulting radio signals can identify tags and communicate information about them, including the tag serial number, product-related data, and other details.
Passive and Active Tags
Passive tags have no internal power source and cannot send their own signals. They wait for a signal from the RFID reader, which is transmitted by radio frequency waves. These waves energize the antenna of the tag, waking up the integrated circuit (IC) and sending back a response. This process is called coupling and is similar to how a bar code scanner works. The low cost of a passive tag makes it an ideal option for larger-scale inventory and asset management systems, as well as for tagging assets in unique environments like cold chain operations.
Active tags have onboard batteries that allow them to emit their own signal and transmit data over a longer range. These tags are often encased in rugged shells to protect the battery and electronic components from harsh conditions. This makes them a popular choice for tracking high-value assets that require a protective environment, such as construction tools and machinery.
The onboard battery in an active tag also allows it to perform a variety of other functions, such as tracking ambient environmental conditions. For example, wire-free active tags can be used to monitor temperature and humidity levels throughout your data center or colocation facility. This type of information can help prevent scalding, moisture damage and even equipment failure.
RFID antennas are a key component in the communication between an RFID reader and RF identification tag. The antenna converts electrical energy into radio waves which get picked up by the tag and converted back into electricity. The RF identification tags RFID Reader use the collected energy to transmit unique identification and data. Antennas are available separately or packaged together with a reader in a single device.
Antennas are made to operate within specific environments and for a variety of applications. The directional capabilities of antennas can help improve read ranges and reduce dead zones in the reader’s coverage area. They are also designed to withstand specific environmental conditions such as extreme heat or cold and moisture. Some are rugged enough to be placed outdoors and others can be mounted on forklifts or other industrial vehicles.
The polarization of the antenna is another important consideration when selecting an RFID system. Linear polarized antennas radiate waves in a specific plane, either horizontally or vertically. This means that if the antenna’s polarity is not aligned with the polarity of the RF identification tag, the read range can be compromised. Circular polarized antennas emit waves in both planes, so that if the tag is oriented at an angle to the vertical the read range will still be good.
Antenna gain (measured in dB) is an indicator of the antenna’s performance and its ability to capture more power from the reader and transmit it to the RFID tag. A higher gain antenna will provide a stronger signal and better reading range.
As you might have guessed, the type of cable you use is critical to your RFID reader performance. Using low loss cable that is cut to the proper length helps reduce your potential signal noise, ensuring that your tags are detected and scanned properly. SkyRFID offers high quality LMR 240 and LMR 400 cable with low loss connectors to help you get the best possible performance out of your RFID reader.
When the RFID tag in the environment desfire ev1 is woken up by the wireless signal, it reflects backscattered information to the built-in antenna of the RFID reader. The reader acquires the wireless signal, demodulates it and extracts the encoded data.
The RFID tag built-in cable 10 with its two folded ends is usually brought to the place where it will be laid out. The individual ID’s of the RFID tags included in the cable are read out by the RFID reader 66 and referred to a database via such a communication channel as the internet.
The data pieces stored in the database include the individual ID’s of the RFID tags built in the segmented cable as well as such data giving the cable starting point and the cable destination point for the respective segmented cable. Additional information such as electric properties is also included in the administration data if necessary.
Many RFID vendors offer development kits that provide the products needed to get started with RFID technology. These kits include the reader, antennas, power supplies and software to test a system. Development kits are available for different frequency readers and are ideal for those implementing RFID technology in an industrial setting. Gateway RFID, for example, sells a ThingMagic development kit that contains the hardware needed to implement read/write capabilities in RAIN-enabled printers and tag commissioning stations. Other manufacturers, such as Alien, also offer development kits for deploying more efficient and manageable RFID solutions in any sector.
Impinj offers a reader chip developer kit for designers looking to integrate high-performance RAIN connectivity into their products. The kit includes hardware designs, firmware and manufacturing support tools that reduce the design time, complexity, cost and risk of bringing new RAIN RFID-powered devices to market.
Another manufacturer, CAEN RFID, provides a software developer kit for its easy2read USB-based readers. According to the company, the kit includes library code that makes it easier to link a reader with middleware or enterprise applications. The library code, based on the C++ programming language, is accessible via the reader’s USB to serial interface.
STMicroelectronics, meanwhile, offers a Nucleo expansion board for its ST25 RFID/NFC reader ICs that simplifies the process of developing an evaluation and prototype. The evaluation kit can be integrated into an embedded system and supports a variety of operating systems, including Microsoft Windows, Android and Linux.