New Design Topology of High-Q Factor Printed Antenna having Unequal Width and Pitch used for Near-field Wireless Power Transmission

In this paper, an unequal printed structure is proposed to obtain high quality factor (Q-factor) coil antenna in wireless power transmission system. In the resonance method wireless power transmission, the quality factor is one of the important factors that determine the transmission efficiency. Generally, the quality factor is increased by increasing the size of the resonator, but through the structure presented in this paper, the quality factor can be maximized without changing the size. In addition, this method can improve the low quality factor of the "printed antenna", which was pointed out as a disadvantage. The main idea to achieve high quality factor is a pitch and width that is not constant along the width. The line pitch and width of the printed pattern are gradually increased in proportion with outer diameter. By using this design method, the Q-factor is increased about 21.8% in comparison with conventionally designed antenna. In addition, it can be confirmed that the antenna performance is substantially superior to that of a typical coil antenna if the size conditions are the same.