Amplifier and transmission solution for 13.56MHz radio coupled to smartcard controller

摘要

An RFID card includes a smartcard controller that receives power from a host device. The RFID card also includes a small inductive device capable of inductive coupling with an RFID reader. The small inductive device is small enough to fit in the form factor of a memory card or SIM card. Enhancement circuits enhance the usable read and write distance of the RFID card.

主权项

1. A mobile device comprising:
a smartcard controller that includes load modulation circuitry for half duplex communication by creating at least one frequency sideband about a carrier frequency of an interrogating radio frequency (RF) field; an antenna tuned to operate at 13.56 MHz; and at least one active circuit coupled between the smartcard controller and the antenna, wherein the at least one active circuit includes an amplifier coupled to be powered by the mobile device, and wherein the amplifier is coupled to amplify a signal received from the antenna and to provide an amplified signal to the smartcard controller, and the at least one active circuit further includes a transmit circuit coupled between the smartcard controller and the antenna that in operation forms a signal that mimics the at least one frequency sideband and wherein the signal drives the antenna.