Low power and high integrated circuits are required due to the development of electronic devices. So that the complexity of the system increases. Therefore, various EMC problems, not previously occurred, are generated. Experts with many experiences designed with enormous time to solve these problems. However, due to the increased complexity of the system, EMC design requires more expertise and advanced technologies.
Therefore, EMC LAB is researching about EMC design using AI. Designing with AI changes various design parameters in complex systems with minimizing process. With AI, the optimal design that could not formulate in the past and the reduced simulation time such as EM and circuit are achievable.

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  A conceptual illustration of signaling channel application to server board

Currently, the utilizations of Unmanned Aerial Vehicle (UAV) are increasing, in the area of surveillance, geometric information, intelligent transportation system, and package delivery. However, the UAV has the on-board power limitation that is caused by the limited battery capacity, and battery capacity increases are accompanied by weight increase, so UAV operation will not be efficient. For this UAV limitation, the applications of wireless power transfer (WPT) technologies to the UAV are drawing attention.

However, the IPT systems for UAV charging require high electric power compared to the portable device. This means that the high density magnetic field will generate around IPT system. In addition, this strong magnetic field could be a leakage magnetic field. This leakage magnetic field influences the negative effect to human. The electromagnetic field (EMF) generating from UAV charger could be the severe safety issues compared to portable device. This is because that the IPT system of the UAV generates a high density magnetic field, but humans can adjacent to the charger like portable device. The active shielding system can be considered as the alternative to reduce the EMF of the IPT system. A principle of the active shielding is to eliminate the leakage magnetic field by generating the cancelling magnetic field. The cancelling magnetic field has the opposite vector direction with the leakage magnetic field so two magnetic fields are eliminated each other in terms of the phasor.

The active shielding system can be considered as the alternative to reduce the EMF of the IPT system. A principle of the active shielding is to eliminate the leakage magnetic field by generating the cancelling magnetic field. The cancelling magnetic field has the opposite vector direction with the leakage magnetic field so two magnetic fields are eliminated each other in terms of the phasor. The independent active shielding system is to supply shielding power from the independent power source. Power supply of the active shielding system is controlled corresponding to the strength and phase of the leakage magnetic field. Based on this control, shielding performance will enhance compared with the precedent shielding method.

In order to reduce leakage magnetic field, Our laboratory has proposed the reactive shielding method. The reactive shielding method is to eliminate leakage magnetic field by generating cancelling magnetic field. The cancelling magnetic field has the opposite magnetic field vector with leakage magnetic field so leakage magnetic field is reduced by cancelling magnetic field. Reactive shield generates cancelling magnetic field by excited leakage magnetic field from TX and RX coil. The advantages of reactive shield is that low heat is generated than aluminium shielding, and application requirement is reduced then active shielding system. In addition, the reactive shielding method is accompanied by low efficiency decreases than precedent shielding method.

Wireless power transfer technology enables to charge electronic devices without any physical wire connections. To transfer the power wirelessly, the time-varying magnetic field is generated from the source coil. Unlike the transformer, the leakage magnetic field due to the large air gap between the coils cannot be neglected. As the WPT technology is more widely used, human exposure to time varying electromagnetic fields(EMFs) accordingly increases. Also, harmonic leakage electromagnetic field generated from WPT systems can affect other electronic application. A method for reducing the leakage magnetic field is required in order to commercialize wireless charging system. However, the conventional electromagnetic field reduction methods need to reduce the volume and weight of shield for implementation.

In our laboratory, we propose a planar resonant reactive shield to reduce the electromagnetic field and harmonic electromagnetic interference. Unlike the other conventional shields, the planar resonant reactive shield requires minimal additional size and reduce the leakage electromagnetic field with negligible degradation in power transfer efficiency.

Currently, to consider the safety issues generated by the wireless power transfer (WPT) system, human exposure to EMF should be assessed and compliance with international safety guidelines and standards (ICNIRP 1998, ICNIRP 2010, IEEE 2002, and IEEE 2005). In particular, for an internal electronics inside the body, the human body exposure should be evaluated by the electromagnetic field radiation emitted from the external source, and also the effect on the device itself should be considered. In addition, if the internal device is charged by WPT, unlike the human exposure from the external source, power transmission and reception occurs via internal human medium, an appropriate assessment method should be developed.