There are a variety of antennas available in the market for a host of applications. Antennas have different properties and specifications, that make them suitable for different kinds of uses. One such type of antenna is the near-field antenna. These antennas are used to create a secure proximity read zone.
You can find these antennas in Credit/Debit card transaction machines, security identification doors, attendance machines, etc. So, let’s discuss more about maintaining a secure read zone using near-field antennas.
What is an Antenna’s Read Zone?
Before we talk about the read zone of an antenna, let’s first discuss how an antenna works. An antenna is a piece of equipment that is essential for wireless transmission of data. Antennas work by converting electronic signals/electricity into electromagnetic signals and broadcasting them outwards. In an RF system, the antenna receives digital signals from the reader and converts them into electromagnetic radiation (radio Waves) to propagate them wirelessly.
Although radio waves are not destroyed after a certain time, according to the inverse square law, they decrease in energy as it travels further and expands. When dealing with radio communication, the signal only remains viable enough to a certain distance, after which it isn’t strong enough to carry data back successfully using backscattering. This is known as an Antenna’s Read Zone; the area where the antenna can successfully communicate with the RFID tag.
Read zones are not like a symmetrical circle or sphere, in practical terms, antennas propagate signals in a curved shape along a specific field of view. In an average RFID communication zone, there are two separate zones/areas of the antenna’s broadcasting field. These are known as a near-field zone, and a far-field zone.
(A). Near-Field Zone
The Near-Field zone refers to the initial area of the broadcast, where the signals are the strongest, and where the tags can communicate using inductive coupling. In most RF systems, this zone is generally extended to a couple of centimeters from the antenna. The signals in this zone are powerful enough that they can induce an electric charge in the tag using electromagnetic induction.
(B). Far Field Zone
On the other hand, the interrogation zone after the near-field zone ends is called the far-field zone. In this zone, the signals are not strong enough to induce electricity in a tag. Therefore, tags in this area utilized radio backscattering to communicate with the reader.
Why Do Some Users Prefer a Close Proximity Read Zone?
Most business operations require the use of both types of read zones, as they both fulfill different applications. For example, in order to program a tag’s chip, you need to keep it in the near-field zone as you need to energize the tag to rewrite the memory. However, due to the limited range of NFC antennas, for tracking purposes, most users rely on far-field antennas.
Near-Field antennas are extremely popular in applications like access control, contactless transaction, tag reprogramming, etc. There is also one additional benefit of using near-field read zones. This is the fact that they provide good security against data capture or communication interception by a third party. As the near field is too small, any unauthorized personnel will need to be in extreme proximity to the tag and antenna to intercept the communication.
How to Create a Close Proximity Read Zone?
The best way to create a proximity read zone is to use antennas designed to communicate in a small area. These are known as NFC antennas. These antennas utilize a coil instead of a standard elongated antenna. The benefit of using a coil is that it creates a stronger electromagnetic field; this happens because the EM fields also pass through the coil and superimpose on itself, creating a stronger field with a smaller radius.
This allows the antenna to energize the tags properly with enough energy in its signals, while also not propagating the signals outside of the NFC read zone.
Some popular examples of Near-Field Antennas are A1115 UHF NFC Antenna, A1163 Near-Field Antenna, Mini-Guardrail UHF Antenna, etc.
Applications of Near-Field Read Zones
As discussed above, proximity read zones of NFC antennas are extremely popular in a variety of industries. So, let’s discuss the popular applications of near-field read zones.
(A). Access Control
The most popular use of this technology has to be in access control applications. Nowadays, most businesses have automated their access control systems. This generally involves the use of RF technology. The users will install an NFC antenna at the access points of a facility that can only be accessed using authorized RFID Smart Cards or FOBs.
(B). Contactless Transactions
Another use of these read zones is in contactless transaction devices. All the bank card readers made for the past couple of years have NFC technology integrated inside of them. This allows them to conduct and authorize transactions without the need to put in the password, making the whole process go a lot smoother.
(C). Data Transfer
Unlike the older generations of smartphones where you had to physically connect phones to a computer to transfer data at a good speed; the newer phones have NFC capabilities, allowing them to transfer large amounts of data to any compatible device within proximity.
(D). Public Transportation
Aside from access to private establishments like company offices, we also use NFC read zone technology in public transportation. Organizations like the DMRC Metro utilizes close proximity read zone access gates that read RF travel passes to allow passengers to enter the platform.
Frequently Asked Questions
Q1. What is the read range of RFID?
The read range of RFID can differ from different types of systems. For example, an NFC antenna is a communication range of a few centimeters; on the other hand, a UHF system can have a read range of 8 to 14 meters. An active tag with an internal battery can be read at a distance of 100 meters.
Another factor that contributes to the read range of an RFID is the energy output of the antenna and its gain.
Q2. What is an RFID zone?
An RFID zone refers to the area around RF antennas that can act as interrogation zones. Meaning, that any compatible tag inside these zones can be read by the reader.
Q3. What is the principle of RFID?
RFID technology works on the principles of radio propagation, much like a radio, smartphone, etc., by communicating using radio signals. There are two methods that an RFID system uses to transmit data through radio waves, namely – inductive coupling, and radiative coupling.
An inductive couple uses electromagnetic induction to induce an electric current within a tag which is then used by the tag to broadcast a carrier signal. On the other hand, radiative coupling uses radio backscattering to reflect signals coming from a reader and send the data through them.
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