How Radio Frequency Identification (RFID) communication occurs.
RF (Radio Frequency) communication occurs by the transference of data over electromagnetic waves. By generating a specific electromagnetic wave at the source, its effect can be noticed at the receiver far from the source, which then identifies it and thus the information.
In an RFID system the RFID tag which contains the tagged data of the object generates a signal containing the respective information which is read by the RFID reader, which then may pass this information to a processor for processing the obtained information for that particular application.
An RFID System can be visualized as the sum of the following three critical components:
- RFID tag or transponder
- RFID reader or transceiver
- Data processing subsystem
An RFID tag is composed of an antenna, a wireless transducer and an encapsulating material. These tags can be either active or passive.
While the active tags have on-chip power, passive tags use the power induced by the magnetic field of the RFID reader. Thus passive tags are cheaper but with lower range An RFID reader consists of an antenna, transceiver and decoder, which sends periodic signals to inquire about any tag in vicinity. On receiving any signal from a tag it passes on that information to the data processor.
The data processing subsystem provides the means of processing and storing the data. RFID systems can also be differentiated based on the frequency range it uses. The common ranges are
- Low-Frequency (LF: 125 – 134.2 kHz and 140 – 148.5 kHz),
- High-Frequency (HF: 13.56 MHz) and
- Ultra-High-Frequency (UHF: 868 MHz – 928 MHz).
Low-frequency systems have short reading ranges. They are most commonly used in security access, asset tracking, and animal identification applications.
High-frequency systems, offering long read ranges (greater than 90 feet) and high reading speeds, are used for such applications as railroad car tracking and automated toll collection. When designing a RFID system the most critical component is understanding the actual environment that the system will be installed in, and this is accomplished by a site survey.
An RFID site survey is a physical survey of the premises where the RFID processes will occur.
A site survey identifies optimal locations for the RFID tags on the products, as well as the optimal locations for readers so the RFID processes work 100% of the time.
When considering the use of wireless equipment, it is extremely difficult to predict the propagation of radio waves and detect the presence of interfering signals without the use of specialized test equipment.
Even with omni-directional antennas, radio waves do not travel the same distance in all directions. Walls, doors, elevator shafts, people, and other obstacles offer varying degrees of attenuation, which cause the radio frequency (RF) radiation pattern to be irregular and unpredictable.
As a result, an RFID site survey should be performed to fully understand the behavior of radio waves within a facility before installing any wireless devices.
The goal of an RFID site survey is to gather enough information and data to determine the number and placement of your work points that will provide the coverage required.
The Remonix Design Engineers spend considerable time discussing with the decision makers of our Clients exactly what to expect from the implementation of their RFID System.