Internal thermometer

Abstract

A miniature spherical-shaped internal temperature transponder. A temperature sensor (,) is fabricated in a spherical integrated transponder circuit (,) which may be placed in the human body by ingestion, implantation, or injection. In one aspect of the invention, a passive system is disclosed whereby an external monitoring station (,) generates an energy field using a magnetic field generator (,) which is coupled to a power coil (,) of the transponder (,). The power coil (,) passes power to a power regulator (,) to provide regulated power to all transponder (,) circuits. Temperature data obtained by the temperature sensor (,) is passed to a voltage controlled oscillator (,) for conversion into an RF signal. A mixing circuit (,) receives the RF temperature signal and modulates the temperature data signal onto an oscillator frequency from an RF oscillator (,). An RF amplifier (,) receives the modulated RF signal from the mixing circuit (,) and transmits it via an antenna (,) to the external monitor station,which is proximate to the transponder (,). The signal is received by an RF receiver (,) and processed using a CPU (,) to extract the measured temperature data, which can then be displayed to the operator on a display (,). The transponder (,) may be powered either by the external electromagnetic radiation source (,) or an internal battery.