Local electromagnetic shielding for thyroid: A study on shielding efficacy and specific absorption rate

This study assesses the shielding efficacy of local electromagnetic shield for the thyroid gland. The investigation employed a mechanical model of a thyroid shield gear, integrating it within a high-resolution three-dimensional virtual model (Duke). The simulation environment and biological electromagnetic model were constructed from 1 to 6 GHz, with the Finite-Difference Time-Domain (FDTD) algorithm. The results indicated that the specific absorption rate (SAR) values of the thyroid were significantly elevated under forward irradiation and in the L band (1–2 GHz). In addition, the local electromagnetic shield reduced the SAR values at the thyroid position, with a shielding efficiency ranging from 15 to 40 dB across the evaluated frequency range. Further, the local shielding effectiveness of the thyroid have obvious variety between frequency and polarization. However, the data also indicated a potential increase in SAR values in other tissues, notably the eyes by up to 4 dB. The study determines that local electromagnetic shields markedly reduce radiofrequency radiation to the thyroid, necessitating a balanced design approach that accounts for both protective benefits and side effects on other tissues. The method and result provide a new perspective and quantitative data for thyroid protection, which has important guiding significance for the design and practical application of electromagnetic protection products.