RFID Reader Basics

RFID Reader Basics

RFID readers transmit radio waves in a specific frequency to activate RFID tags. When a tag enters the reader’s detection range, it responds with a return signal that contains information about the item, such as its serial number.

Unlike barcode scanners that require line-of-sight scanning, RFID readers can collect data from items from several meters away. This makes it easy to work with large amounts of inventory, even in crowded conditions.


In the RFID detection process, the reader sends out a wireless signal that detects the tags. The signal, which carries the information to be identified, is reflected by the tag and backscattered into the antenna connected to the reader. The signal is then demodulated in the control module of the reader and passed to a computer for processing. This is the same technology used to scan lost pets at animal shelters. The microchips contain the pet’s name and contact information so they can be returned to their owners quickly if they are found.

RFID systems provide many benefits in the supply chain. They increase productivity and reduce work time by eliminating manual data entry and improving accuracy. The system can also track products in transit, even when they are packaged, to prevent stockouts. Additionally, the amount of information stored in an RFID system is incredibly superior to barcode systems, allowing for individual product traceability.

RFID readers can be handheld or mobile devices, or RFID Reader mounted into vehicles such as forklifts. Fixed readers are mounted into portal configurations or in other stationary locations, such as a doorway. RFID readers can connect to a variety of different antennas, depending on the area of coverage required for your application. Some readers may use multiple channels to mitigate frequency selective fading and co-channel interference.


The RFID reader, also known as the brain of the system, transmits a signal to the antenna that causes it to emit radio frequency waves. When these waves hit an RFID tag, they activate the chip inside the label and send back information to the antenna. The antenna then transforms the data into a digital signal that can be read by other RFID readers or connected devices, such as smart phones and tablets.

An RFID system can read hundreds of labels in seconds, which helps improve productivity and efficiency in tasks. It can also provide more accurate product identification, which is useful for reducing shrinkage in inventory and warehouse management processes. Additionally, the data can be transmitted in real time to other systems, making it easier to track products and their movements.

In a clothing retail setting, for example, an RFID deployment in fitting rooms makes it possible to track which styles are selected by customers and where they’re tried on. This information can help retailers and brands increase sales and optimize product placement.

An RFID reader’s reading range depends on its gain, which is determined by how efficiently the antenna can convert a digital signal into an RF signal. Another important factor is the antenna’s polarity, which must match the polarity of the RFID tag. The most common type of RFID tag is passive, meaning that it does not have a battery but gets its energy from the electromagnetic field generated by the RFID reader/antenna combination.


A reader transmits radio waves that activate a tag’s transponder and send back a signal with information encoded on it. To receive this data and interrogate the tag’s contents or write to it, the RFID reader must have an antenna that’s compatible with the transponder frequency. The RFID reader antenna can be either integrated within the device or sold separately. Integrated readers are compact and more mobile, but they lack the flexibility of external hardware.

The size of an RFID reader’s antenna is important because it can affect the read range. Bigger antennas have a higher gain and a wider RF field, while smaller ones have lower gains and narrower fields. To choose the best antenna for an application, start by outlining your read zone and choosing one with a size that fits.

Antennas come in a variety of shapes and sizes, with many different connectors. Some are desfire ev1 small and more hidden, while others are sturdier and work well in harsh environments. Connector types also vary, with RP-TNC and SMA being the most common.

The polarization of an RFID reader antenna is another important consideration. The polarization of the RFID tag and reader should be matching, or the reading performance will degrade. Antennas with circular polarization deliver stable delivery of UHF energy in a radial symmetrical pattern, so they can detect tags regardless of their orientation.


In RFID, a microchip holds data to identify objects or products and transmits it via radio waves to an antenna, which turns the information into usable data. The tags have an antenna, too, which is activated when it comes into the range of the reader to respond with its own signal. The tags can be passive, drawing their energy from the reader’s electromagnetic field, or active, with batteries providing their power. The RFID system can then integrate with any other computer or ERP data systems used by a business to manage this data. The RFID system is also less prone to orientation issues, as the tags do not need to be oriented in order to be detected. This is a distinct advantage over bar code and magnetic stripe technology.