Several factors that affect the read and write distance of UHF RFID products

Radio Frequency identification (RFID) is a wireless communication technology that can identify a specific target through radio signals and read and write related data without establishing mechanical or optical contact between the identification system and the specific target. An RFID system generally consists of four parts: electronic tag, antenna, reader and application software. Because it is a wireless communication technology, it is vulnerable to the interference of various wireless signals in the air and the impact of the space environment, so its application effect is related to the field space environment, so the key comes, UHF RFID product reading and writing is mainly related to what factors?

When people learn about UHF RFID products, the first question they usually ask is how far your reader can read. In fact, such a question is difficult to simply answer is how much distance, because the actual read and write distance in addition to determine the performance of the reader, but also by the reader's radio frequency power, antenna gain and polarization direction, the unit length of the feeder attenuation and total length, the performance of the label, the label and the relative position of the reader antenna Angle. Of course, the surrounding physical environment will also affect the distance of reading and writing, but if it is not a particularly harsh environment, the impact is not the main, and this impact can not be predicted in advance of its extent, only to the actual field test to know. Read/write distance is related to several factors (in addition to the performance of the reader and tag itself)

1, if the reader RF power is small, the read and write distance is close, on the contrary, if the power is large, the read distance is far;

2, related to the gain of the RFID antenna, the gain of the reader antenna is small, the read and write distance is nearby, anyway, the gain is high and the read distance is far;

3, the label and antenna polarization direction and relative Angle of the degree of cooperation, the direction of the same degree of cooperation is high, read and write distance is far, on the contrary, do not cooperate with the read distance is close;

4. It is related to the total length of the feeder connecting the reader and the antenna. The longer the feeder, the closer the read and write distance is.

5, with the feeder unit attenuation, the greater the attenuation, the closer the read and write distance, on the contrary, the attenuation small read distance.

In general, we usually say that my reader can read how many meters, in fact, this is only in a specific condition and environment measured data, leave this specific environmental conditions, such numbers are strictly meaningless, at most can only be used for reference, because there is no unified testing environment and authoritative testing department.

There are also two points that need to be explained: first, the distance of writing data to the label is generally 40%-70% of the distance of reading data from the label, because writing requires more energy than reading; Second, usually people think that UHF RFID is only suitable for long-distance applications, in fact, it can be from zero distance to long distance, and the closer the distance requirement, the easier it is to achieve.