RFID is an abbreviation for Radio Frequency Identification. It’s a technology that uses electromagnetic fields to transmit data that a receiver catches from an RFID tag. It is mostly one-way: tag -> reader. The reader is also referred to as interrogator.
A tag at least consists of a chip or circuit and an antenna. There are active, passive and semi-passive tags, where the active version has it’s own power-source (so this adds to the components), the passive one is completely powered by the reader and the semi-passive one has a powered chip or circuit, but data transmission is powered by the reader. Tags can be read-only or read-writable.
RFID can operate on a variety of frequencies, like low-frequency (LF), high-frequency (HF), ultra-high-frequency (UHF), microwave etc., ranging from 120 kHz upto 24,125 GHz. The used frequency as well as the type of tag play a role when it comes to the range a tag can be read from. We are talking about 10 cm - 200 m. gaylord M FOCker - ready to pwn your MIFARE tags
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