A Capacitorless Self-Resonant Antenna for Wireless Power Transfer

This paper designs a kind of capacitorless self-resonant printed spiral antenna (SR-PSC) systems for wireless power transfer (WPT). The highest efficiency of the designed spiral antenna is 68.7% at an operating frequency of 700 MHz for the WPT system. And the frequency band of ~38 MHz is achieved for a transmission efficiency of no less than 50% with 20 mm air gap. The profile is only 60 × 60 mm which means it can be used in the restricted space and can also reduce the cost of adding additional components.