Modeling and Simulation to Evaluate the Specific Absorption and Thermal Effect of Antennas Coated with Various Biomaterials

Abstract

Antennas are essential elements in medical communications systems, but their use poses significant challenges related to electromagnetic and thermal safety. Reducing the specific energy absorption rate (SAR) and limiting thermal rise are basic requirements to ensure the safety of these systems. In this work, analyze and evaluate the effect of coated biomaterials on the electromagnetic and thermal performance of an implanted antenna operating at 2.44 GHz, taking into account different body compositions. The analysis included four coating cases no coating, PDMS coating, PDMS + Graphene composite coating, and PDMS + Ferrite composite coating, at different PDMS layer thicknesses. It is focused on analyzing and evaluating the reflection coefficient, specific absorption rate, and steady-state thermal rise.  The analysis was done by simulating the antenna model and adding complementary elements to it, and from the results it can be said that the PDMS + Graphene composite coating leads to an almost complete decrease in the SAR values of  0.18 W/kg at BMI = 17, W/kg 0.01 at BMI = 22, and 0.07 W/kg at BMI = 27 across all BMI values, but this decrease results from a very high reflection of electromagnetic energy, which indicates weak coupling. Electromagnetic and low radiation efficiency, and the PDMS + Ferrite composite coating achieved the best balance between safety and efficiency, recording a realistic and significant reduction of 0.18 kg ≈ SAR at BMI = 17, 0.01 W/kg ≈ SAR at BMI = 22, and W/kg ≈ 0.07 at BMI = 27.