## 1 Introduction  
Electromagnetic exposure brings about extensive effects and hazards to human health, which are mainly in the form of damages and carcinogenic effects to the central nervous system, immunological function, cardiovascular system, reproductive and genetic systems, visual system, etc. [1]. Electromagnetic energy carried by an electromagnetic wave is absorbed by an organism to cause systematic or local body temperature increases, subsequently leading to physiological and behavioral changes. Exposure to high-intensity electromagnetic radiation of different frequencies results in varied impacts on the human body ranging from slight neuropathic pain to excitation of tissue and fever of the skin, which results in a thermal effect and triggers an internal thermoregulatory reaction, increasing body temperature to the extent of endangering human health. The consequence of this can be fatal in some cases. The amount of electromagnetic influence imparted on an organism during the interactions between it and electromagnetic radiation is called the bioelectromagnetic dose. Given that a wide range of factors such as wave (including frequency and polarization), body (including the type of tissue, the posture of the body), and also environment (indoor or outdoor) contribute to the interactions between electromagnetic radiation and the tissues of humans and animals, accurate calculation of the internal electromagnetic field in organisms such as humans and animals can be quite complicated. Presently, the specific absorption rate (SAR) [2] is recognized by the academic circle as a dosimetric measure for electromagnetic exposure evaluation, used for a quantitative description of the energy of an electromagnetic field that is taken in by bio-tissues. It is defined as the power absorbed per mass of tissue and has units of watts per kilogram (W/kg). Theoretical dosimetry and experimental dosimetry are two approaches to acquire SAR. Theoretical dosimetry refers to theoretical calculation of the internal electromagnetic field distribution or power absorbed by organisms (animal, human, or certain parts of the human body) under the effect of certain electromagnetic fields (far field or near field). It enjoys the advantage of objectively describing the interactions between the electromagnetic field and organism by creating a complicated anthropomorphic voxel phantom based on medical tomography characterized by imaging systems including CT, MRI, and theoretical calculations employing well-proven methods (e.g., Finite Difference Time Domain, FDTD) [3; 4]. Academics of the National Radiological Protection Board of the UK, [PERSON] et al. [5], created a male phantom NORMAN in 1997, which is known as the first high-precision anatomical anthropomorphic phantom, with an accuracy up to 2 mm, lattices of whole body up to 9 \(\times\) 10\({}^{9}\), and classified into 37 kinds of tissues. Their continuous efforts led to the creation of NAOMI in 2005, the first adult female phantom [6], and proceeded to the establishment of anthropomorphic voxel phantoms of a group of five young children (three boys and two girls) [7] in 2007. Apart from phantom creation, calculations based on anthropomorphic voxel phantoms are drawing ever-increasing attention from scholars in many countries. By calculating electromagnetic radiation SAR under different postures of the human body using an anthropomorphic voxel phantom, [PERSON] et al. [8] concluded that the majority of radiation sources reached the maximum level within the range of several millimeters from the body's surface, while the radiation distribution differed greatly with changes of postures. With regard to experimental dosimetry, measurements and calculations based on anthropomorphic phantoms are typically used. The metrics include the electric field intensity, tissue temperature increase, infra-red thermogram, etc.