4 ms·
NFC is not really a radio. Basically it uses a loosely copled transformer. Works much closer than 1 wavelength and only magnetic field matters.
by IndrekR 3y ago
NFC is not really a radio. Basically it uses a loosely copled transformer. Works much closer than 1 wavelength and only magnetic field matters.
- fourier54 3y ago100%. Every time I read the term "antenna" when referring to the coil used for NFC/RFID I suffer inside...
- Isamu 3y agoGood point, NFC is described as operating in a particular RF band but not through radio waves: > As with proximity card technology, NFC uses inductive coupling between two nearby loop antennas effectively forming an air-core transformer. Because the distances involved are tiny compared to the wavelength of electromagnetic radiation (radio waves) of that frequency (about 22 metres), the interaction is described as near field. An alternating magnetic field is the main coupling factor and almost no power is radiated in the form of radio waves (which are electromagnetic waves, also involving an oscillating electric field); that minimises interference between such devices and any radio communications at the same frequency or with other NFC devices much beyond its intended range. NFC operates within the globally available and unlicensed radio frequency ISM band of 13.56 MHz. Most of the RF energy is concentrated in the ±7 kHz bandwidth allocated for that band, but the emission's spectral width can be as wide as 1.8 MHz[57] in order to support high data rates. https://en.m.wikipedia.org/wiki/Near-field_communication https://en.m.wikipedia.org/wiki/Near-field_communication