An improved radio frequency identification (RFID) tag and related reader system and process are provided, wherein the RFID tag includes an on-board battery for enhanced signal transmission range, relatively rapid signal transmission speed, and optimized completion of a data transaction between the tag and a reader. The RFID tag further includes a power management system for activating the tag battery on an as-needed basis, and for thereupon enabling limited portions of the tag circuitry as required for a specific communication protocol, thereby conserving battery power and prolonging battery service life. In one preferred form, the battery is integrated with an antenna structure of single or dual mode with respect to frequency or type. This combination battery-antenna may be designed for recharging from a source of ambient energy.