The wireless power transfer (WPT) method for electric vehicles (EVs) is becoming more popular, and to ensure the interoperability of WPT systems, the Society of Automotive Engineers (SAE) established the J2954 recommended practice (RP). It includes powering frequency, electrical parameters, specifications, testing procedures, and other contents for EV WPT. Specifically, it describes the ranges of self-inductances of the transmitting coil, the receiving coil, and coupling coefficient (k), as well as the impedance matching values of the WPT system. Following the electrical parameters listed in SAE J2954 RP is crucial to ensure the EV wireless charging system is interoperable. This paper introduces a method for adjusting the effective permeability of the ferrite blocks in the standard model, to tune the self-inductance of the coils as well as the coupling coefficient. To guarantee the given values of the self-inductance of the coil and coupling coefficient matched those in the standard, we slightly modified the air-gap between the ferrite tiles in a specific region. Based on this method, it was possible to successfully tune the self-inductance of the transmitting coil and receiving coil as well as the coupling coefficient. The proposed method was verified by simulation and experimental measurements.

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A simple wideband planar antenna with a separated fence structure is presented in this study for 4/5G base station application. To improve the front-to-back ratio (FBR) and half-power beamwidth (HPBW) of the proposed antenna, five parasitic separated fence structures are designed. This design can effectively suppress the surface wave propagating along the metal ground and increase the radiation performance of the proposed antenna in the low elevation area. After integrating the fence, the FBR of the proposed antenna is improved by 6 dB on average. And the HPBW is increased by 19 °on average above 3 GHz. Furthermore, a 1 � 4 linear antenna array is designed and analysed. The measured results display that the proposed antenna achieves a wideband of 47.3% (2.22-3.64 GHz) for |S 11 |≤ −10 dB with an isolation higher than 30 dB, which are in agreement with the simulations. The average HPBW, FBR, and gain of the proposed antenna is about 8522 dB, and 6.9 dBi in the operating band. K E Y W O R D Sfront-to-back ratio, half-power beamwidth, low elevation, planar antenna, surface wave, widebandThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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