RFID reader how it works ?
RFID （Radio Frequency Identification）with a unique identification number for each item and just like a bar code card/label or magnetic strip card, the RFID tag/card must be scanned by a passive RFID reader device and retrieve the identifying information.An rfid reader writer software has two parts:
A rfid reader and antenna,some RFID reader with external antenna,they are rfid readers what is working in frequency of 860-900mhz long distance or 13.56 mhz long range.
The external antenna reader designed for passive RFID reader get long range , like 1m range 2m range or 10 meter.
But the intergrated reader with short reade distance. RFID reader 125khz/13.56Mhz/ with USB or ethernet or RS232 RS85.
Some RFID readwer with intergared antenna with 0.5cm to 100cm distance. The RFID antenna propagates the wave in both vertical and horizontal dimensions. The field coverage of the wave and also its signal strength is partially controlled by the number of degrees that the wave expands as it leaves the antenna. While the higher number of degrees means a bigger wave coverage pattern it also means lower strength of the signal. Passive RFID tags utilize an induced antenna coil voltage for operation. This induced AC voltage is rectified to provide a voltage source for the device. As the DC voltage reaches a certain level, the device starts operating. By providing an energizing RF signal, a reader can communicate with a remotely located device that has no external power source such as a battery.
A transponder – the RFID tag – that has been programmed with information by RFID reader writer .
RFID tag how it works ?
In most of the RFID tag system, passive RFID tags are attached to all items that are to be tracked. These passive RFID tags are made from a tiny tag-chip that is connected to an antenna. The tag chip contains memory which stores the product’s electronic product code (EPC) and other variable information so that it can be read and tracked by RFID readers anywhere. An RFID reader is a network connected device (fixed or mobile) with an antenna that sends power as well as data and commands to the passive RFID tags. The RFID reader acts as an access point for RFID tagged items so that the tags’ data can be made available to business applications.
RFID Frequency Band AllocationThere are many RFID frequencies, or RFID frequency bands that RFID systems may use. There is a total of four different RFID frequency bands or RFID frequencies that are used around the globe.
RFID Tag antennas collect energy and channel it to the RFID chip to turn it on. Generally, the larger RFID tag antenna’s with more energy and the longer read range. RFID Tag antennas can be made from a variety of materials; they can be printed, etched, or stamped with conductive ink, or even vapor deposited onto labels. The RFID tag antenna not only transmits the wave carrying the information stored in the tag, but also needs to catch the wave from the reader to supply energy for the tag operation. Tag antenna should be small in size, low-cost and easy to fabricate for mass production. In most cases, the RFID tag antenna should have omnidirectional radiation or hemispherical coverage. Generally, the impedance of the RFID tag chip is not 50 ohm, and the antenna should realize the conjugate match with the tag chip directly, in order to supply the maximum power to the RFID tag chip.