**1. Introduction**

Deliver long-range power over great distances is very interesting in the future. For this reason, the Wireless Power transfer (WPT) is a versatile modern technique that can be used by a range of electrical devices. Batteries play an important role in the mobility but have a high initial cost and a short life. For example, the first application of quick wireless charging has been applied in vehicles for public transportation in the traditional bus stations [1]. This form of application has such a small distance between stations and a short waiting period that it has been readily embraced by the WPT for electrical charging. Furthermore, research into EV wireless charging while driving or parking is really appealing and is helping to grow the industry [2]. Another case in point is the spread of so-called commercial electronics. This sector has already seen commercial successes of these WPT systems, particularly for smart-phone chargers, due to the problem of limited battery time and the large use [3]. Although it is difficult to realise those applications because the power must penetrate a thick material like the skin, the benefits of using a WPT device are definitely clear in implantable equipment for health care [4]. Wireless power distribution removes the need for percutaneous cables or surgeries to replace batteries, which may be uncomfortable and infection-prone. This results in a reduced size and lighter weight, or the removal of an energy storage feature that provides patient comfort. In both of these implementations, the propagation distance is critical to the application's reliability.
