The card has a pattern of gold electronic contacts on the back of the card. The microchip processor is embedded under the contacts. The card must be inserted into a reader to be used. The card communicates using radio signals. Antenna is within card.
Power is generated within card from radio signals.
Also available are hybrid cards which can be used in both modes Smart Cards contain a microchip which is essentially a personal computer without a screen or keyboard. The have their own operating system, working memory and storage. The newest cards can be programmed using a version of Java. Many of the cards that are referred to as smart cards are really memory cards, that is, they only contain a memory chip - they have no processing capability or built in security. Many phone cards fall into this category.