“RFID antennas are directly responsible for RF signal capture and read range. It directly affects the overall performance of the RFID system.”
It is common knowledge that technology has been a significant factor in running a successful business. From billing of items to actually looking for a certain item inside a retail store, technologies like QR codes, RFID, and BLE play an important role. Use of RFID (Radio Frequency Identification) in retail is not a recent phenomenon though it is true that RFID has witnessed a significant retail application over the last decade. In fact, retail is currently the largest business sector using passive UHF RFID tags and chipless RFID tags, using it for item-level tagging and tracking.
RFID is a wireless AIDC (automatic identification and data capture) technology that uses radio frequency (RF) signals to communicate between an RFID tag and an RFID reader using electro-magnetic signals. When a retail merchandise is tagged with an (passive UHF) RFID tag, it can be identified and tracked using the unique tag ID. When in range, the RFID tag antenna captures the RF signal coming from the RFID reader, and power the passive UHF tag. The tag then sends the encoded data to the RFID reader and the reader decodes the tag data for the end users.
Of all these components of the RFID system such as RFID tag, RFID reader, RFID antenna and a RF subsystem (computer interface), RFID antennas play a significant role. RFID antennas are directly responsible for the RF signal detection, capture and the read range in an RFID system.
What is an RFID Antenna?
An RFID antenna is typically a plastic housing of a substrate metal backplate and a coil made of wire (copper, al, au, pure iron etc.), in circular or square/rectangular loop(s). The voltage generated in the antenna is calculated using Faraday’s law and electromagnetic induction law is used to calculate the inductance of the antenna coil.The circular loops are generally used in low frequency (LF) range antennas and the square or rectangular coil is used in high frequency (HF) or ultra high frequency (UHF)
RFID antennas, as mentioned before, are directly responsible for RF signal capture and read range. It directly affects the overall performance of the RFID system. The RFID tags typically come with a build-in antenna along with the IC/chip whereas some RFID readers don’t come with RFID antenna and need additional antenna to function and some RFID readers (known as integrated RFID readers) come with in-built antenna.
What RFID Antenna You Must Buy for Retail Operations?
While choosing a correct RFID integrated reader or RFID Reader antenna for your retail operations, item-level tagging needs, you must look at some technical points that are very important from the performance point of view.
1. Frequency range of the antenna/Reader i.e. LF- 125KHz, HF- 13.56MHz, UHF- 860-960 MHz.
2. Form factor for in-counter, on-counter POS needs,
3. Polarization, circular or linear. Linear one needs proper alignment with the tag while the circular one doesn’t.
4. The read-range of the antenna/integrated reader should be high as Circular polarization antennas lose about 3 dB, about half the energy, as the signals travel in 2D plane.
Now that we are clear on some technical specification, let’s understand some more points for choosing correct antennas for retail item-level tracking and identification.
The RFID antennas should be rugged enough to be use in outside environment such as retail warehouse, entry and exit gates etc. The antenna should be seamlessly and successfully integrated with your customer facing environment. It should come with flush or VESA- studded mounting option for POS and indoor /outdoor mounting needs.
Various RFID antennas are available in the market that are best suited for indoor retail installation and Point of Sale needs but keeping the high customer facing environment in mind you should choose high performance, circular polarization antenna that does not have alignment issues (360 degree efficiency) and enables efficient communication between the tag and the reader. In retail environment when items are being scanned in thousands every hour, the RFID antenna should be able to produce powerful, long range signals pretty quickly.
Typically for retail and inventory use, an RFID antenna with 3 watt power, 5dBiC gain, 1.4 VSWR loss, -10dB front and back loss ratio will do the work pretty efficiently.
To conclude, since retail business is high customer intensive, RFID reader and antenna that you can use must be circular polarized for multidirectional coverage and linear polarized for unidirectional coverage. Since thousands of retail transactions take place every hour, the antenna must be high performing and should be easily integrated in the retail store and inventory, with other systems.