Occultamento di grandi strutture metalliche impiantate nel corpo umano mediante materiali magnetici = Cloaking of large implanted metallic structures in human body using magnetic materials

Biomedical implants are used in case of damaged bones and tissues to restore physiological functions in the human body. For this purpose, many metals such as titanium alloys are used as implants which are then covered with another material for biocompatibility to avoid corrosion and other harmful aspects of metals. When subjected to electromagnetic waves, it gives a particular electromagnetic response that is very different from a human bone, making it detectable through metal detectors and other equipment. We want to simulate the same response as in a bone structure only when these implants are subjected inside the human bone. Cloaking is a technology that makes different materials partially or fully invisible to the electromagnetic spectrum or for particular frequencies. To cloak these implants usually periodic materials are used to cover these materials to have the same response as in the case of a bone. However, periodic materials, when used for a flat surface, are easy to design and manufacture. As cylindrical or conical implants have to be inserted in a bone to support broken bone, cloaking with these periodic materials becomes difficult as these flat surfaces need to be bent and joined at the end. These structures undergo different stress on the outer and inner radii. Thus, we do not get a uniform response throughout the geometry, usually when bent or joined. To solve this issue, we have used magnetic materials to avoid periodic materials and design complexity. Firstly, the response of a human bone with the respective muscle, fat, and skin covering is studied. Then, the implant alone with a dielectric inserted, and the response obtained. Thus the deviation between these two responses is reduced by covering the implant and dielectric with magnetic material to get the same response as the bone structure. Then biocompatibility is obtained by covering this structure with a bio-compatible material inside the bone.