Implementation of planar inverted-F structure for wireless charging radiator

This paper presents the design of radiator for wireless charging application using meandering form technique of spiral shape. The proposed wireless charging radiator is designed on a 1.6mm thick FR4 epoxy dielectric substrate workable at the frequency of 13.5MHz. To improve the performance of radiator, the method of planar inverted-F structure is implemented by adding a short pin at the end of radiator. This method can enhance the value of S₁₁ wherein simulation result of the radiator without planar inverted-F structure has S₁₁ value of -13.27dB, while the radiator with planar inverted-F structure has S₁₁ value of -37.73dB. Beside enhancing the value of S₁₁, the use of planar inverted-F structure is reducible the overall size of radiator by cutting off the radiator strip up to 2.617m. Therefore, by implementing planar inverted-F structure the size of radiator is 240mm × 240mm with the length of radiator strip from the probe to the short pin as far as 5.993m.