Reduction of radiated emission from resonance coil in GaN wireless power transmission circuit by using Nd–Fe–N magnetic material
Toshihide Ide,
Nobuyoshi Imaoka,
Mikio Oomori,
Kimihiro Ozaki,
Mitsuaki Shimizu,
Noriyuki Takada
Affiliations
Toshihide Ide
AIST-NU GaN Advanced Device Open Innovation Laboratory (GaN-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 464-8601, Japan
Nobuyoshi Imaoka
Magnetic Powder Metallurgy Research Center (MagMet), National Institute of Advanced Industrial Science and Technology (AIST), Chubu Center, Nagoya, Aichi 463-8560, Japan
Mikio Oomori
Electronics and Photonics Research Institute (ESPRIT), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Center 2, Tsukuba 305-8568, Japan
Kimihiro Ozaki
Magnetic Powder Metallurgy Research Center (MagMet), National Institute of Advanced Industrial Science and Technology (AIST), Chubu Center, Nagoya, Aichi 463-8560, Japan
Mitsuaki Shimizu
AIST-NU GaN Advanced Device Open Innovation Laboratory (GaN-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 464-8601, Japan
Noriyuki Takada
Electronics and Photonics Research Institute (ESPRIT), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Center 2, Tsukuba 305-8568, Japan
In this study, the Nd–Fe–N materials are employed as an electromagnetic shield, for the first time, for the resonance coil in the 13.56-MHz-GaN wireless power transmission circuit. The Nd–Fe–N materials are introduced into the air-core resonance coil as the cap of the edges or the core. By using Nd–Fe–N, the radiated emission from the resonance coil is reduced because the electromagnetic field distribution is shrunk due to the effect of not the imaginary part but the real part of the permeability. When the spectrum of the magnetic field of the resonance coil is measured at the frequency from 30 MHz to 800 MHz, the intensity of the higher harmonics radiated emission is restricted by Nd–Fe–N in all of the frequency ranges. In particular, the Nd–Fe–N capped air-core coil shows the superior characteristics in both the shielding effect and the power loss. In addition, by numerical calculation, it is found that the effect of the electromagnetic shield will be enhanced by increasing the real part of the permeability by optimizing the Nd–Fe–N material fabrication.
