Superficial heat reduction technique for a hybrid microwave-optical device

Area of Science:

• Biomedical Engineering
• Electromagnetics
• Thermal Physiology

Background:

• Localized heating of biological tissue is crucial for studying thermoregulation.
• Existing microwave applicators face challenges in controlling energy deposition and superficial heating.
• Optical monitoring systems integrated with applicators can provide real-time physiological data.

Purpose of the Study:

• To propose and evaluate a circularly polarized microstrip patch antenna as a microwave applicator for localized deep heating in biological tissues.
• To compare the electromagnetic energy deposition and thermal patterns of circularly versus linearly polarized antennas.
• To investigate the potential of this applicator for thermoregulation studies using an integrated optical system.

Main Methods:

• Computer simulations were employed to model a biological tissue (skin, fat, muscle) with relevant dielectric and thermal properties.
• Electromagnetic (EM) energy deposition and specific absorption rate (SAR) were calculated for both circularly and linearly polarized antennas.
• Thermal distribution was simulated using the biological heat equation to assess heating patterns.

Main Results:

• The circularly polarized antenna demonstrated more efficient deep tissue heating compared to the linearly polarized antenna.
• For equivalent muscle SAR, the circularly polarized antenna resulted in lower SAR at the skin-fat interface.
• Simulated thermal distribution showed reduced heating in superficial layers with the circularly polarized design.

Conclusions:

• The proposed circularly polarized microstrip patch antenna is an effective applicator for localized deep heating in biological tissues.
• This design offers improved safety by minimizing superficial heating, making it suitable for thermoregulation studies.
• The applicator, coupled with an optical monitoring system, holds promise for advancing the understanding of human body thermoregulation.