US Patent 8085130 Radio frequency identification tag

A battery-assisted radio frequency identification (RFID) tag having a battery-assisted circuit and a filter is provided. The battery-assisted circuit generates a radio frequency signal whose frequency is outside an operating frequency band of the RFID tag to supply additional power to the RFID tag. The filter filters the radio frequency signal output from the battery-assisted circuit before the RFID tag demodulates a reader command, so that a modulation depth of the read command is less affected by multi-carrier. By using the battery-assisted circuit and the filter, the RFID tag has a longer read range and is less affected by multipath fading effects.