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Can RFID reader have only one antenna?
A design of RFID reader antenna including a fixture, which is equipped with a chip-attaching machine producing the RFID tags, is presented. Such an antenna is constrained to read exclusively one tag only for the purpose of functional check of the whole tag when it passes the reader antenna.
Technically, all RFID readers can interrogate only one tag at a time. If two tags are sending signals to a reader simultaneously, there is no way for the device to distinguish one from another.
Which type of antenna is used in RFID tag?
Most UHF tag antennas are designed with a dipole-type structure. This means they generally are long and thin visually, and operate similar to a magnet.
How are reader antennas used in the RFID system?
Reader antennas convert electrical current into electromagnetic waves that are then radiated into space where they can be received by a tag antenna and converted back to electrical current. This design RFID system is used to track object placed on a storage rack. In this system, there is two component of RFID.
What is the axial ratio of a RFID antenna?
Axial Ratio is defined as the circular polarization of the RFID antenna – only for circular not linear antenna. This is the ratio between the maximum and minimum linear gain. Low Axial Ratio antennas allow for more tags to be read with the same power output of another antenna with a higher Axial Ratio.
What makes a RFID tag have a longer read range?
As a general rule of thumb, small tags will have shorter read ranges, and large tags will have longer read ranges. In order to get the best range from any RFID tag, make sure that the tag is fully facing the antenna and pay particular attention to tag orientation when using linearly polarized antennas.
When to use a linear polarized RFID antenna?
Since the RFID antenna continuously emits a wavelength the rotational field will eventually cover any tag that is in its path. This is best to use when tag orientation is unknown, but you lose at least 3dB when compared to a linear polarized antenna.