RFID Readers and Tags
RFID readers can obtain data from tagged items quickly and accurately, increasing productivity and eliminating unproductive work. This technology also provides individual product traceability.
The reader transmits a radio frequency, wakes up the RFID tag in the environment, and receives the wireless signal reflected by it. The reflected signal carries information such as the tag’s protocol, managing organization, and asset description.
What is an RFID Reader?
Radio frequency identification works with tiny microchips that have information stored on them. To read a chip, RFID readers send out an energy field that wakes up the tag and induces a current in its antenna. The tag then transmits data back to the reader in response. This technology has been widely adopted by supply chain companies for use in tracking inventory items and assets, as it streamlines the process so that human workers can focus on more value-added work.
RFID readers, also called interrogators, can be divided into three distinct categories based on their mobility: fixed RFID readers, mobile RFID readers and USB readers (which are plugged into desktop computers). The type of RFID reader required depends on the size of the inventory, the amount of data to be read, and the reading range needed.
Unlike barcode scanners, RFID readers don’t require a direct line of sight to read tags, so they can be used in tight spaces and for moving products or materials. Additionally, RFID systems can read the contents of a container or box without needing to open it. This can significantly improve worker productivity by reducing the time employees spend scanning products and processing inventory data. It also reduces errors by eliminating manual steps and automating the process. In addition, RFID tags provide individual product traceability for each item, a critical function that is not available with barcodes.
Types of RFID Readers
The heart of every RFID system is the reader, which is also referred to as an interrogator. The reader sends radio waves that activate the RFID tag and receives a return signal from the tagged item. The reader then translates the return signal into data.
A variety of readers are available, depending on your needs. Some are able to connect to the Internet via WiFi, which allows them to operate as part of an enterprise-level system. Others can connect to a RFID Reader mobile device using Bluetooth, which makes them portable for use in the field. There are even USB readers that can be plugged into a computer for desktop applications.
Other factors to consider when choosing an RFID reader include power and range. Some readers are able to perform hundreds of readings in a second, which can significantly boost productivity and efficiency in inventory tasks. They can also work in harsh environments and high temperatures.
You can also find RFID readers with integrated antennas, which are ideal for indoor applications without a high volume of tagged items. They can be aesthetically pleasing and designed to suit a specific application. Finally, there are development kits that can be purchased from the reader manufacturer and provide all of the components needed to get started testing RFID tags. These kits typically include the reader, a recommended antenna and a few sample tags.
Power Sources for RFID Readers
An RFID reader transmits radio frequency (RF) energy, which is absorbed by an embedded tag. The tag then reflects that energy back with encoded data to the reader via a backscatter signal. The reader captures this signal, decodes it and sends the data to a connected system. To make this process work, the RFID reader and tag must be compatible – meaning they must use the same carrier frequency and, if encryption is used, the same keys.
To achieve the longest possible read range, a power source that is electrically quiet and has low ripple is required. For this reason, batteries are commonly used to provide the power required for RFID reader operation. These are available in a wide variety of voltage and amperage ratings to suit different RFID applications.
Most RFID readers allow users to choose between a minimum transmit power and a maximum, so they can fine-tune the sensitivity of their systems. This is a more advanced calculation than simply determining a reader’s transmit power, and it takes system cable loss and antenna gain into account. It is important to remember that decibel figures are on a logarithmic scale, so decreasing a reader’s transmit power by 3 dBm doesn’t represent a 10% reduction in power as it may seem. This is why a good knowledge of system specifications is essential to choosing the right power source for your project.
Antennas for RFID Readers
Antennas for RFID readers transmit power from the reader in the form of RF waves to RFID tags. Antennas can be built into readers to save space and cost, or external antennas are available for more configuration options. RFID desfire ev1 antennas can be circular or linear polarized and come in a variety of sizes.
The antennas used with RFID readers must be compatible with the specific tag type and frequency. In addition, they must be able to operate within the global operating region for the RFID system in order to ensure compliance with ISO and EPCGlobal Gen 2 standards.
Choosing the right RFID antennas for your application is essential to optimize performance and read range. For example, directional RFID antennas create a cone-like field and provide longer read range than omni-directional antennas. Linear polarized antennas emit electromagnetic waves in one plane while circular polarized antennas emit them in two planes (helix, crossed dipoles or patch). This allows RFID tags to be read regardless of their orientation. However, circular polarized antennas have less gain than linearly polarized ones.
Antenna connectors must also be compatible with the type of reader and cable selected. Most antennas use N-type, RP-TNC or SMA connectors, which are commonly found on RFID reader cables. Connectors affect the amount of power that can be transmitted between the reader and antenna, which can influence read range. They also impact the ability of an antenna to be positioned near metal, which may degrade performance.
