ABSTRACT
Wireless power transmission (WPT) is gaining more momentum for powering electronic devices without any direct electrical contact. Inductive coupling, coupled-mode magnetic resonance, capacitive coupling, and ultrasound are among conventional WPT techniques that have widely been investigated. Inductive coupling is known as the most suitable method for short-range WPT due to its high power transmission efficiency and safety. Inductive coupling covers a wide range of applications with different power requirement from nanowatts in some wireless sensors and radiofrequency identification tags to milliwatts in implantable medical devices (IMDs), watts in mobile electronics, and kilowatts in electric vehicles. Wireless IMDs are good examples of where short-range WPTs using inductive coupling can be very effective to remove transcutaneous wires or bulky batteries with limited lifetime. Inductive coupling principle is based on Faraday's induction law, which states that when the total magnetic flux through a conductive loop varies with time, a current is induced in the loop itself.
