Circular vs. Linear Polarization Antenna| Which is the right RFID Antenna? And Why?
We found many of our customers have no idea on Circular polarization & Linear polarization antenna. This article gives a explanation on their differences.
Q1: Why we should think about whether we choose a Circular or Linear polarization antenna for our RFID system?
A:Cause the circular or linear polarization can make a significant difference in RFID system.
Q2:What's their differences.
A: Linear polarization occurs when electromagnetic waves broadcast on a single plane (either vertical or horizontal). Linear polarized antennas must have a known RFID tag orientation and the RFID tag must be fixed upon the same plane as the antenna in order to get a consistent read. Example of linear polarized antenna is the SR-AU-BZ120
Due to the concentrated emission, linear polarized antennas typically have greater read range than circular polarized antennas of the same gain.
Circular polarized antennas, such as the SR-AU-BZ090, the electromagnetic fields is in a corkscrew-like fashion. Technically speaking, they are broadcasting electromagnetic waves on two planes making one complete revolution in a single wavelength.
Compared to linear polarized antennas of the same gain, circular polarized antennas will have a shorter read range because they lose about 3 dB splitting their power across two separate planes.
When deciding which type of antenna to purchase for your RFID system, understanding the how these antennas work as well as how the RFID tags should be oriented with respect to the antennas is key.
If all the tags you need to read will be on the same plane and aligned with the plane of the antenna, then you should consider a linear polarized antenna. If your tag orientation is not something that will be reliable or consistent, then you will likely need to use a circular polarized antenna.
Also there are more other antennas such as Omnidirectional antennas, panel antennas, PCB ceramic antennas, mat antennas etc.... All types of antennas were designed for different deployment environment in RFID systems.
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