A wireless batteryless in vivo EKG and body temperature sensing microsystem with adaptive RF powering for genetically engineered mice monitoring

A wireless, batteryless, and implantable EKG and core body temperature sensing microsystem with adaptive RF powering for untethered genetically engineered mice real-time monitoring is designed, implemented, and in vivo characterized. A packaged microsystem, exhibiting a total size of 9 mm times 7 mm times 3 mm with a weight of 400 mg including a pair of stainless steel EKG electrodes, is implanted in a mouse abdomen for real-time monitoring. A low power 2 mm times 2 mm ASIC, consisting of an EKG amplifier, a PTAT temperature sensor, an RF power sensing circuit, an RF-DC power converter, an 8-bit ADC, digital control circuitry, and a 433 MHz FSK transmitter, is powered by an adaptively controlled external RF energy source at 4 MHz to ensure a stable 2 V supply with 156 muA current driving capability for the overall microsystem.