The RFID technology has made tremendous progress over the last decade in terms of application and deployment. It has become cheaper and affordable. The costs of various components in an RFID system including RFID tags, RFID readers and RFID antennas as well as RFID software have come down significantly boosting more demand, a total reversal of how demands and prices actually work.
The RFID technology has become so prevalent that many businesses directly and indirectly depend on it for automatic data collection and identification of tagged assets, the supply chain and logistics, manufacturing, and retail being the top contenders. In fact, it was the retail giant Wal-Mart that started a pilot project in 2003 to implement RFID technology in many of its store, mandating the suppliers to tag supply boxes with RFID tags for better inventory management. The project proved successful and met the objectives set but the cost of implementation was too high at the moment and lack of sharing the results with the supplier lead to discontinuation. Now in September 2022, Walmart again issued a mandate asking suppliers in home, toys and electronics categories to tag assets with RFID tags.
RFID, short for Radio Frequency Identification is a wireless, Automatic Identification and Data Capture (AIDC) technology that uses radio frequency signals to transmit and receive data. It employs a set of RFID tag, RFID Reader and antenna to work. The RFID antenna here plays a crucial role in capturing the radio frequency (RF) signals, providing a longer read-range.
How RFID Tag Antenna Works?
RFID tags are attached to objects for tracking and identification purpose. These tags are mainly active (consists batteries for power and transmitting signals) and passive (no batteries). A passive UHF RFID tag utilizes the RF signals coming from the reader to power up the tag.
The RFID tag antenna catches the electro-magnetic signals coming from the RFID reader and converts it into electrical current that powers the Integrated circuit (IC chip) in the tag. The antenna then modulates the data in the tag memory and backscatter the signal after modulation. This signal is then captured by the RFID reader.
RFID tag antenna plays the crucial role of changing the signals from electro-magnetic to electric current and then back to electro-magnetic signal.
How RFID Reader Antenna Works?
An RFID reader is another crucial component in an RFID system. It is used to interrogate an RFID tag and decode the data for the end user. When in use, the RFID reader sends a powerful radio frequency signal/electromagnetic signal which is received by the RFID Tag Antenna.
RFID reader antenna also receives the signal backscattered by the RFID tag and converts it into an electric signal, which is then decoded by the RFID reader. The data, thus received is saved in the batch memory of the reader which could be up to 40000 RFID tags (like Zebra RFD90).
The RFID reader sometimes comes with an integrated antenna and sometimes the antenna is separate and not housed together with the reader (as in some fixed readers like Zebra FX9600 RFID Reader). The antenna plays a crucial role in interrogation as it successfully propagates the interrogation signal coming from the reader to a longer range. It not only increases the performance of the RFID reader but also the complete RFID system in place. It also ensures the even weak signals coming from some tags are also received by the reader, without fail.
How to Choose an RFID Antenna? UHF RFID Reader Antenna
As I explained before, the RFID tag houses an IC chip and an antenna together. So, you don’t need a separate antenna for the RFID tag. It comes with the RFID tag.
But some RFID readers don’t come with antenna and you need to buy one. Let’s see some of things you need to ensure while buying an antenna:
- Operating frequency range i.e. LF- 125KHz, HF- 13.56MHz, UHF- 860-960 MHz.
- Compact design/form factor
- Polarization, circular or linear. Linear one needs proper alignment with the tag.
- Read range, LP antennas offer high read range in comparison to a CP antenna of the same gain as CP antenna lose about 3 dB, about half the energy as the signals travel in 2D plane.
At present 9dBi antennas are immensely sought after as they provide decent read range without losing much power. In application such as Vehicle fleet management, shelving systems, inventory management, real-time asset tracking etc., linear polarized 9dBi antenna is often used.
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