An antenna is an essential component of any wireless communication system. Its entire purpose is to generate & propagate radio waves. The same is in the case of Radio Frequency Identification technology. RFID systems can use different types of antenna depending on the application and other factors. Presently in the market, there is a variety of RFID antenna types available for purchase. So, what is the difference between these antenna, and does it matter when it comes to applications?
Today, we will discuss exactly that and how to choose the correct antenna type for your business.
What is an RFID Antenna?
It is a component on the receiving end of an RFID system. As the name suggests, an RFID antenna is responsible for broadcasting interrogation signals from the RFID reader and receiving signals from RFID tags. Generally, readers use external detachable antenna and can be connected with multiple antenna.
There are several types of antenna based on the technology and applications. However, before that, let’s see how an RFID antenna works.
How Does an RFID Antenna Work?
An antenna works by creating radio signals with the help of oscillating electrons. To clarify, sounds travel through wires in the form of electrons vibrating at different frequencies. When these charges enter an antenna, it starts to vibrate along the antenna and generate radio waves. These waves hit an RFID tag and the tag reflects a part of the signal back towards the antenna. The antenna absorbs the signal, sending it in digital form to the reader. The reader translates it into readable format.
Types of RFID Antenna
Due to the vast applications of radio frequency identification technology, manufacturers have developed a variety of different kinds of antenna.
Far-Field
These antennas are designed to specifically pick up on radio signals broadcasted from the far field of the antenna. That does not mean that they don’t have a near field, by default the initial zone around the antenna will be near field. But these are finely tuned to communicate efficiently with far-away RFID tags.
Near-Field
These antennas have a very short range of readability. They operate strictly on a near-field communication basis. They generally have a read range of 10 centimeters.
Ground Antenna
These antennas are made to withstand large physical loads like people, bikers, vehicles, trolleys, etc. These antenna are used in environments like warehouses, hospitals, production lines, sporting events, etc.
Linear Polarized
Polarization refers to the direction in which signals propagate from a reader’s antenna. Linear polarized antenna signal travels along a single plane/axis. These signals have a longer communication range, but they can only read RFID tags that are aligned in the same plane as them.
Circular Polarized
These types of antennas propagate signals in multiple directions, the signals broadcast in a spiral pattern around the antenna. The benefit of these antenna is that you don’t need to orient the tags in a particular plane for this system to function. However, these antenna have a significantly smaller read range than linear polarized antenna.
Multi-Purpose
As the name suggests, these antenna are compatible for use in multiple types of applications. These are small and flexible, made out of very durable materials like fireproof ABS plastic. Multi-purpose antenna can provide accurate asset tracking for both long-range & short-range operations. These are designed with the latest technology.
Cabinet/Shelving Antenna
These antennas are designed specifically to be placed discretely within cabinets and shelves. These antenna are slim and usually broadcast near-field signals. You can use these for inventory management and even in retail applications like display cabinets in jewelry stores.
How to Select the Correct RFID Antenna for Your Business?
There are many factors that you need to keep in mind while selecting an RFID antenna for your business. As RFID antenna come in all shapes, sizes, and ranges, selecting the correct one can streamline your entire operation and save you a lot of money. So, let’s check out some of the most important things to keep in mind before purchasing RFID antenna.
Read Range/Size of Facility
The first thing you need to keep in mind is the size of your facility. Different antenna have different broadcast & read ranges, depending on various factors like operational frequency, type of polarization, input power, etc. In large enough facilities, you will need to deploy multiple antenna per reader.
Application
Secondly, while selecting RFID antenna, you need to keep in mind the application you need them for. Depending on the application your specification requirements for the antenna will change. For example, if you need to deploy an RFID system for display cases in a retail store, then you’d want an antenna that operates using NFC. On the other hand, if you want to use RFID in production lines, then you’ll prefer using UHF linear polarized antenna capable of fast reading speed that scans along a single plane.
Antenna Size
As mentioned above, antenna come in all shapes and sizes, with different specifications. An antenna can be as small as a couple of centimeters in dimensions to a couple of feet. They can be circular, cylindrical, rectangular, etc. Depending on where you want to deploy the antenna, i.e., the space available, the shape of the fitting surface, distance from or obstacles between the tags and antenna, you can select from a variety of products.
Ingress Protection Rating
Also termed “IP”, this is an international safety rating standard that shows the level of protection a device has against damage from solids or moisture. An IP rating consists of two digits, the first digit ranges from 0 to 6. This displays the protection level against solids like dust particles. The second digit can range from 0 to 9 and refers to the level of protection against liquid pressure & moisture. Depending on the type of application and surrounding environment you can select different IP-rated items.
Frequency Standards
Radio Frequency Identification systems operate by communicating wirelessly using radio waves, as the name suggests. To work properly, the tags, antenna, and readers must operate at the same frequencies/frequency ranges. There are certain standards from frequencies set up by regulatory organizations, namely – the US (set by the FCC), EU (set by the ETSI), and Global. The US standards for UHF RFID support frequencies ranging from 902 to 928 MHz, EU supports 865 to 868 MHz, and Global from 860 to 960 MHz. The global standards cover all the frequencies, but they are also less accurate than the US and EU standards following products. The wider the frequency range, the less accurate it will be.
Pricing
The RFID antenna price is a crucial factor to consider, as it contributes significantly to the overall cost of an RFID setup. When it comes to purchasing RFID antennas, the pricing can vary significantly depending on the range, specifications, and features you require. Generally, the longer the read range and the more advanced the technology, the higher the price tag.
Beam Width
Lastly, antenna have different angles of the width of the beam it broadcasts. The beam width is indirectly proportional to the effective broadcast range, due to the inverse square law. The tighter the beam width, the more gain an antenna will have. So, depending on the distance between the tags and the antenna, the setting of the tags, etc you can go for a wider beam width antenna or narrower.
Frequently Asked Questions
Q1. What is the range of an RFID antenna?
RFID antenna can have different read ranges, depending on factors like frequency, power input, beam width, etc. Businesses use RFID antenna with reading ranges differing between a couple of centimeters to a little over 100 meters.
Q2. What is RFID reader antenna?
A reader antenna is an essential component of an RFID system. These antenna are responsible for broadcasting a radio signal that allows communication with the RFID tags. These antenna act as a transceiver and capture the signals coming from the tag and send it to the reader.
Q3. Do RFID tags have antennas?
Yes, an RFID inlay consists of a chip and an antenna. The antenna on RFID tags work as a transponder, they are usually activated when they receive a radio signal from the reader and reply with a preprogrammed response.
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