Electronic passports have secure contactless smart card technology embedded in the back cover. Contactless refers to the fact that it is a wireless device, something like a cell phone except it can only communicate over very short distances of an inch or two. Smart card means it contains a microprocessor, a small but real computer, and special security software to protect the identity of the passport holder.

Contactless smart card technology is NOT the same as RFID. See, What are the differences between contactless smart cards and RFID?