Factors to Consider When Buying an RFID Reader
A RFID Reader sends radio frequency (RF) signals through an antenna that are absorbed by tags and returned to the reader with information. The reader then decodes the data and transmits it to a connected system.
Fixed RFID readers are used in warehouses to reduce labor for scanning inventory and preventing theft of items. They are also used on toll roads to allow drivers to pay with prepaid accounts.
Battery Life
The battery life of an RFID reader is an important factor to consider. Since RFID tags can be attached to physical money, clothing, and possessions as well as implanted in animals and people, the possibility of reading personally-linked information without consent has raised privacy concerns. Thankfully, standard specifications address these concerns and help ensure that RFID data is only accessible to authorized parties.
Passive RFID chips are powered by a fluctuating magnetic field generated by the RFID reader’s interrogating radio waves. The electromagnetic waves activate the capacitor in the chip and power it up, enabling the card to respond by sending back a signal. These responses can be encrypted with user-defined data to protect sensitive information, and the chip’s lifetime is essentially unlimited.
Active RFID tags, on the other hand, are powered by a battery that needs to be recharged. They are only “woken up” by a radio signal from the RFID reader and only transmit when they receive a command. This conserves battery life and reduces maintenance costs.
The ALR-S350 offers powerful RFID tag reading performance combined with a long battery life to make it ideal for heavy inventory tasks. This makes it a smart choice for the Bring Your Own Device (BYOD) business trend that has become popular with many organizations. It’s also a great choice for those who want to separate the RFID capability from their mobile device to avoid having to purchase additional accessories like a cradle and power supply.
Sensitivity
The sensitivity of an RFID reader depends on several factors. Among other things, it can be affected by temperature, humidity, and the distance between the tag and the reader. A high sensitivity reader can detect a tag from a greater distance than a low sensitivity reader.
When an RFID tag is triggered, it wakes up and sends backscattered signals through its antenna to the reader. These wireless signals contain a variety of information, including signal strength, phase value, and Doppler shift. The RFID reader uses this information to identify the tag.
COTS readers use a technique called frequency hopping to mitigate frequency selective fading and co-channel interference. This means that the reader changes frequency channels every 0.2 s. This can cause phase RFID Reader values to change discontinuously, which makes positioning or detection more difficult.
RFID readers are used in a variety of applications, from unmanned supermarket checkouts to electronic identification of motor vehicles. The RF front end of an RFID reader consists of an RF transmitter, local oscillator (LO), and receiver analog baseband circuit.
In a typical application, the digital core of the RFID transponder IC handles the data flow with the reader, following the EPC Gen-2 communication standard. This is a major power consuming block and needs to be designed for efficiency. Most of the time, the RFID Reader digital core utilizes non volatile memory (NVM). This can be achieved by using either an electronically erasable and programmable ROM (EEPROM) or a ferroelectric random access memory (FeRAM) which are both power efficient.
Range
RFID tags are powered by electromagnetic energy that strikes conductive material on the tag. The resulting electrical current powers an integrated circuit (IC) inside the tag that transmits data to the reader via radio waves. The reader receives the signals from the IC and interprets them into usable information. Many factors affect the range of an RFID reader.
Temperature, humidity, and other environmental factors can change how much energy the IC on your tag emits, which in turn will change how far the signal travels. This is especially true for high-frequency ultrahigh-frequency RFID tags (UHF).
Check your reader settings and make sure the receiver sensitivity is set to its maximum setting. The higher the sensitivity, the better your reader will be at picking up weaker tag signals that are farther away. Power settings also have an impact on reading range. As a rule of thumb, your reader’s transmission power will double every 3 dB you increase it, but this doesn’t necessarily mean you’ll double the range.
What you’re tagging your item with and how you’re positioning it can also significantly reduce read range. Metal-mount and water-resistant tags, for example, can drastically diminish a passive UHF tag’s ability to communicate with a reader due to the reflection or absorption of RF energy by metal or liquids. Additionally, using long cables can add unwanted loss to your system and limit the distance your RFID antenna will reach.
Programmability
The ability to identify individual items or boxes of products without needing line of sight, brings a new level of productivity to logistics and manufacturing processes. RFID also enables the monitoring of large quantities of stock quickly and reliably, thus saving time and resources.
The programmable IC chip in an RFID tag enables the storage of much more data than a simple barcode, as well as providing additional functionality, such as security or environmental conditions. Additionally, because of the high read rates provided by UHF RFID systems, large numbers of tags can be detected at once, and their status – whether they are in stock or on the move – can be monitored rapidly and accurately.
Depending on the application, different reader capabilities are required, and this is where programming comes in. Most RFID readers use a digital baseband to process the signals from the IC, either via electronically erasable and programmable ROM (EEPROM) or ferroelectric random access memory (FeRAM). The digital core is the major power consuming block in an RFID transponder IC, so it needs a low voltage programming method that minimises power dissipation to increase reading performance.
It is also important to consider the format of the data on the programmable IC, because this affects how an RFID tag responds to the signals sent by the reader. A common example is the facility code, which is used to distinguish a card or tag from other cards with the same programmed data.
