**1. Introduction**

For more than 60 years, biomedical implantable device have been available. Earl Bakken designed and developed for the cardiac pacemaker in 1957, the first transistorized biomedicinal implanted device [1]. The most important issues of biomedical implants, namely patient safety and comfort, have been investigated. The result is a reduction in energy consumption and an efficient transfer of energy to the implanted devices [2]. For implanted devices therefore, the transfer of wireless energy is an important issue. The power supply is a major technical challenge. If a battery is to be used due to its limited size and lifetime, an operation must be performed in a living body to swap the battery [3]. To prevent this invasive operation, a method of wireless transfer of power from outside the body should be developed [4]. The recent focus for biomedical applications is on wireless power transmission (WPT) due to its important benefits, such as facilitating implant surgery in which we avoid connected cable, improving rechargeable reliability, increasing healthcare workers and patients'safety [5]. The potential of WPT technology will introduce the new generation of safe and efficient medical devices [6]. The development of a system for nerve stimulation, cochlear aids, retinal implants, infusion pumps, pacemakers, cerebral pacemakers and others, has recently gained attention by wireless transfer of power (WPT). At the beginning of the 21st century, despite its high weight quality, limited lifetime, and chemical effects, certain applications for medical implanted devices (MID) were operated. The charging cables also had disadvantages and theoretically required a long time. In the early 21st century [7] Wireless Power Transfer Methods (WPT) received significant research interest in biomedical implants and neural prostheses Patient tissue safety is one of the key factors in the WPT design for MIDs. The tissue safety is very much dependent on the body's EM constitutive parameters: the microwave power density, the frequency, tissue absorption and the sensitivity of the tissue. The effects of radio frequency waves cannot immediately be felt (and damages occur) by the patient as lower-frequency waves penetrate deeper into the tissue offering lower absorption. The relative allowability and conductivity of the human tissue decreases and increases with increasing frequencies, thereby increasing tissue absorption. Microwaves penetrate less and heat the tissue more easily at higher frequencies. The main tissue safety measure is the specific absorption rate for wireless power transmission applications for MIDs (SAR). When the electromagnetic wave travel through the tissue, it will penetrate the tissue but part of the wave will be absorbed by the tissue and get dissipated as heat. The interaction between the electromagnetic wave and the tissue depends on the dielectric properties of the tissue and the operating frequency. The amount of power absorbed by the tissue during the interaction is called specific absorption rate (SAR). The WPT proposed five methodologies: inductive transmission of energy (IPT) and capacitive transmission of power (CPT) and acoustic transmission of power (APT) in the neighborhood, as well as middle and remote field (RF) radiation [8]. The inductive links and the radio frequency are the two types of biomedical links (RF). A short-range communication chanal that needs a coil antenna in the area of the output source is an inductive connection. On the other hand, the advantages of RF telemetry are reaching longer distances and improved information rates. In this regard, research is focused on implantable medical equipment connected to RF [9].
