**8. Conclusion**

This chapter presents a study of wireless power transfer technologies. A survey of employing several techniques such as inductive coupling, **resonant inductive coupling,** strongly coupled magnetic resonance, and capacitive coupling for increasing the power transfer efficiency for WPT systems. Metasurface-based WPT systems are also discussed. Many recently published WPT designs are listed with a highlight for the used techniques. Microwave Power Transfer (MPT) also introduced, and two rectenna designs are described.
