An RFID tag without a battery. When radio waves from the reader reach the chip’s antenna, the energy is converted by the antenna into electricity that can power up the microchip in the tag. The tag is able to send back information stored on the chip.

The trend of embedding microprocessors in everyday objects is termed as Pervasive Computing or Ubiquitous Computing.

Describes the orientation of the polarization of an electromagnetic wave. We distinguish between linear and circular polarization. Linearly polarized wave can be aligned vertically or horizontally.

Cards with a range of 7 to 15 cm are referred to as ISO 14443 as Proximity Coupling card. Proximity cards communicate at a frequency of 13.56 MHz.