RFID Readers and Antennas

RFID Readers and Antennas

A RFID Reader is an electronic device that sends out a radio wave to read information on an RFID Tag. These tags are attached to objects or people and can then be tracked.

Most RFID readers come with a Software Development Kit that includes sample programs and API access so that a developer can begin creating their own applications for the reader. Another connector rule is that opposite genders connect – so if the RFID reader has a female connector, the cable would need to have a male connector.


An RFID reader works either autonomously or under the RFID Reader control of external software. In both cases, it needs power. It receives the voltage needed from an integrated or detachable USB cable that connects to a computer for data interfacing and power. The power supply should be an uninterruptible power system to protect the reader against short-term loss of the supply voltage.

The RFID tag does not have its own power source so it draws energy from the radio frequency (RF) signals generated by the reader’s antenna. When the RF signal is emitted from the reader, the tag’s antenna absorbs the energy and transmits back to the reader the information stored on its chip. This is referred to as backscatter. The RFID reader then interprets the information and passes it to a connected system for processing.

This technology allows a high number of readings per second, which improves productivity and efficiency in tasks like scanning or labeling. It also enables the capture of additional data, such as sensor measurements.

RFID readers can identify an item without direct line of sight and can penetrate nonmetallic objects. The ability to scan items in the dark, in a moving environment or at high speeds makes this technology particularly useful for inventory tracking and supply chain management. In retail, for example, RFID systems allow the tracking of styles from the warehouse to the dressing rooms. In addition, RFID can tell the store how often a style was selected and where it was tried on.


Antennas are responsible for transmitting and receiving RF signals that interact with RFID tags. They have different characteristics optimized for end-user applications and play a critical role in ensuring that RFID systems are capable of consistently producing the reliable data demanded in the business world.

The more power an antenna has, the greater its ability to emit a signal that can reach RFID tags in the vicinity. This is known as gain. Antennas also come in various shapes and sizes, with varying levels of performance. These vary by manufacturer and model and are designed to accommodate the space and environment in which they will be used.

Linear and circular polarized antennas are both compatible with RF identification tags. However, linear polarized antennas have more power and can better read tags that are oriented in a single plane whereas circular polarized antennas work best with tags that have a directional field.

Regardless of which type of antenna you choose, it is important to test your system under the circumstances in which it will operate. Reflection, diffraction and absorption will affect the theoretical read zone, as will interference from cellphones, power lines, WiFi, engines, motors or anything else that may generate EM waves.

Antennas can either be integrated into RFID readers (as in the case of handheld devices or some all-in-one terminals) or external to them. Integrated devices are generally smaller, more compact and easier to use in difficult working environments than two separate devices, but external antennas offer more configuration and application options.


Cables are the link between an RFID reader and the antenna. They are typically coaxial cables with a connector at each end that are available in a variety of lengths. Cable type and insulation rating are important because they impact how much energy is transferred from the reader to the antenna. For example, a coaxial cable with a high insulation rating can transfer more energy to the antenna than a low-insulation-rated cable.

The connectors are also important because they dictate what type of cables can be used to connect the hardware. The wrong type of desfire ev1 cable can cause the system to fail and result in a significant amount of time spent trying to resolve the issue. Luckily, there are some basic rules to follow to ensure the correct cable is ordered and installed.

Using a RFID tag to identify assets and products can provide many benefits including inventory management, improved workflows and cost savings. In retail, for instance, RFID tags can be attached to physical items to protect against theft by customers (shoplifting) or employees (shrinkage). Tags can also provide an electronic ‘kill’ signal when activated, helping to improve security in the event of a break-in or other loss.

RFID technology is also used to monitor and control stock inventory in warehouses. The tags can be affixed to or integrated into the product and can store information like a barcode, serial number or more detailed data such as manufacturing or tracking details. They can be active or passive and transmit a radio wave that can be interrogated by an RFID reader to communicate the data.


Depending on the manufacturer of your RFID reader, you may need software to help you manage or configure it. For example, the software that comes with a Zebra fixed RFID reader allows you to easily deploy, optimize and monitor your fleet of readers from a single application.

Once you install the RFID reader and its software, you can begin to collect data. The software allows you to create event handlers for attaching a tag to the reader (rfid_Attach), detaching the tag from the reader (rfid_Detach) and having the tag move out of range of the RFID reader (rfid_TagLost).

With these events, you can process the ID information that was read. For example, if you want to create a listbox that lists the unique tag ID for each item you’ve tracked, put this code within the rfid_TagLost event. This way, the listbox will be updated once for each tag that moves over and then off of the RFID reader.

You also need a software program that can communicate with the RFID reader and decode customer-specific card numbering formats stored on MIFARE, DESFire and iClass cards. This can be done through the built-in keyboard wedge, file logging or direct integration APIs, without exposing the security data encoded into the tag’s encoding scheme.