An Electromagnetic Metasurface for Impedance Matching in Microwave Biomedical Applications

This paper presents the design of an electromagnetic metasurface (MS) to be employed as a matching layer to improve the electric field transmission inside the human body, for microwave imaging and sensing. The approach used to develop the matching layer is based on the transmission line model and it can be useful to tailor the metasurface properties for different applications. In particular, by retrieving the MS impedance and tuning it in order to compensate for the body impedance, the reflection coefficient at the air-tissues interface can be minimized. Through accurate full-wave simulations performed over a preliminary test-case, we demonstrated that the conceived MS is capable of improving the transmitted electric field by 6.6 dB at 1.61 GHz. Moreover, the array reduced dimensions (56 mm × 56 mm) allow to realize systems suitable for different anatomical districts. The obtained results show the possibility to improve the electric field transmission inside human body at microwaves, leading to safer and more effective solutions with respect to the actual state-of-the-art.