Ultra-miniature wireless temperature sensor for thermal medicine applications

Area of Science:

• Biomedical Engineering
• Microsystems Engineering
• Medical Devices

Background:

• Accurate temperature monitoring is crucial for effective thermal medicine procedures.
• Existing sensors often face limitations in size, invasiveness, or power requirements for targeted applications.

Purpose of the Study:

• To present a prototype design for an ultra-miniature, wireless, battery-less, implantable temperature sensor.
• To enable minimally invasive temperature monitoring for thermal medicine applications such as cryosurgery, hyperthermia, and thermal ablation.

Main Methods:

• Designed a sensory device <1.5 mm diameter and 3 mm length for hypodermic needle deployment.
• Integrated a temperature-sensing core (PTAT circuit), wireless data communication, and wireless power reception in 0.15 μm CMOS technology.
• Utilized a second-order sigma-delta analog-to-digital converter (ADC) for digital temperature readout and backscatter communication.

Main Results:

• Developed a fully integrated, all-CMOS implantable temperature sensor prototype.
• Achieved high absolute accuracy in temperature sensing using a microwatt chopper-stabilized op-amp and dynamic element-matched current sources.
• Demonstrated wireless power delivery and data communication capabilities for the implantable sensor.

Conclusions:

• The developed ultra-miniature sensor offers a unique capability for 3D temperature field reconstruction in treated areas.
• This technology has significant potential for enhancing precision and outcomes in thermal medicine.
• The fully integrated CMOS design minimizes size, cost, and enhances reliability for medical applications.