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We proposed EM-wave absorber with periodic patch antennas. It has two feed points on a square patch. We simulated electromagnetic field of patch antennas having infinite periodic structures by using FDTD method and designed at 2.4GHz band. Then, we manufactured and measured the EM-wave absorber for 2.45GHz. As a result, both H- and V-polarized waves could be absorbed at 2.4GHz.
The application of UHF radio-frequency identification (RFID) systems is rapidly increasing. However, because band near the frequency for the UHF-RFID system is also used with the cellular phone, the influence on UHF-RFID system is worried. Prepare the Faraday cage is easy to solve this problem, but generally it shields external noise frequency by broadband. So, It makes difficult to using wireless...
This paper describes a measurement method of electromagnetic shielding effectiveness in low frequency. In order to measure the magnetic shielding effectiveness, loop antennas are usually used. When a type of shielding material is sheet or cloth, it is easily put up inside a loop antenna. Therefore, we propose a method to measure a magnetic shielding effectiveness of materials whose type is sheet or...
The determination of the ground structure in terms of its electric parameters (resistivity and permittivity) is a key point for calculations of ground electrical conduction, especially when high voltages are involved. A mixed optimization method designed to determinate the resistivities and lengths of the ground layers in a horizontally stratified model for the soil is presented, using the Genetic...
This paper describes that the ferromagnetic resonance (FMR) frequency shift can be calculated by an electromagnetic field simulator based on the Maxwell's equation although the relative permeability and the FMR frequency is defined by the Landau-Lifshitz-Gilbert (LLG) and the Kittel's equation. We evaluate the magnetic circuit model with the leakage magnetic flux path for considering the demagnetizing...
The MMW (Millimeter-wave 30 GHz ? 300 GHz) exposure is limited by ICNIRP guideline. Provided guideline for MMW band is based on small amount of data, therefore accumulation of data is desired to evaluate the validity of the guideline. The ocular injure caused by MMW exposure is highly depend on the temperature elevation in the anterior part of the ocular tissue with the complicated structure. The...
Electrostatic discharges (ESDs) due to the collision of charged metals cause serious malfunctions in high-tech information devices. In particular, the fast collision provides severe ESD events, while the mechanism has not fully been elucidated, though the approach speed is known to affect a spark length. In this study, to investigate this mechanism experimentally, we developed a setup for electronically...
In this paper, we propose a method for deciding the parameters to satisfy the experiment values, and also checked the effectiveness of this method based on Kramers-Kronig relation. In our proposed method, we are expressed as matrix the Sellmeier formula, and are solved the simultaneous equation until the satisfied experiment curve. Numerical results are given by the influence of pulse responses utilizing...
Wireless power transfer technology is expected to be one of key technologies to offer easy and safe power supply as well as battery charging and thus to contribute to smart community through various kinds of products, such as portable digital devices and electrical vehicles. This paper mainly focuses on EMC issues on wireless power transfer, including emission which may cause the interference to other...
The wind power generation systems in Japan have been damaged by lightning, especially in winter season. It is caused by the large energy of the winter lightning and several protection methods have been investigated based on the observations of lightning.
The practical approach to implement a 1 Ω current probe with verification for measuring the IC conducted emission is proposed. The 1 Ω/150 Ω direct coupling method is reviewed and the considerations on improving the applicable bandwidth of 1 Ω method are discussed. The critical component, 1 Ω resistor which dominates the frequency response, is designed. The realized 1 Ω probe was fully certified with...
Recently malfunctions of telecommunication installations caused by switching noises of electric equipment or devices have been increasing. The switching noises usually have low frequencies between 2 kHz and 150 kHz. This paper shows some electric interference examples of telecommunication system cause by ac mains noises in frequency range from 2 kHz to 150 kHz. This paper also shows a necessity of...
This paper describes an original methodology for the modeling of parasitic inductive couplings. The key idea is the use of magnetic hooks which are gates for magnetic fluxes that cross conductive loops and consequently induce parasitic voltages, thus disturbing the signal integrity. The multiple connected domains of integrated circuits are modeled by a Magneto-Electric-Equivalent-Circuit (MEEC), consisting...
Five examples of EMC issues in traction power supply system will be shown in this paper. The examples shown in this paper do not cause severe problems in the existing railway system but they should be taken into account to realize reliable traction power supply system and power supply system for station as particular issues in the railway system. Each example is discussed based on the measured data...
This paper reports standardization activities in CISPR and introduces newly developed limits and measurement method of conducted disturbances at the DC ports of Grid Connected Power Converters (GCPCs) applied to solar-photovoltaic power (PV) generating systems. First, background of standardization activities on the development of the limits and measurement method is described. Second, the two proposals...
Impedance matching techniques were previously investigated for maximum power transfer efficiency in wireless power transfer system (WPT). In this paper, similar discipline is investigated and analyzed for reducing magnetic EMC in wireless power transfer system. Basic theory is reviewed, leading to appropriate application in the WPT system while investigating and analyzing the EMC reduction effect.
In this paper, the electromagnetic compatibility issues of wireless powered electric vehicle are discussed in the view of electromagnetic field and electromagnetic interference. The magnetic field reduction for human exposure for near field is investigated and the definition of electromagnetic interference measurement is discussed.
Recent equipment uses many inverters from the viewpoint of energy saving. The inverter circuits have a potential of disturbance source because the high voltage and high speed switching devices are used in the circuits. In this paper, we investigated the relationship between the switch timing difference of inverter circuit and the common-mode voltage on the cable. First, we investigated the mechanism...
Conductive noise from vehicle equipments which contain inverter circuits has been increased by the demand of higher switching operation of power devices in order to improve the power efficiency. On the other hand, since the vehicle equipments are required to minimize the volume, the noise filters should be built-in the housing of inverter circuits. In this case, it is necessary that the conductive...
Since the loss of input rectifying diode bridge in the conventional PFC circuit reduces the efficiency, the bridgeless PFC circuit has been proposed. However, the performances of EMC in some bridgeless PFC circuits are unsatisfactory. In order to improve noise performance, the noise mechanism should be investigated as the first step. In this study, common mode noise current of conventional bridge...
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