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The emissions from the power line communication (PLC) system should be investigated for the influence to the electromagnetic environment. The method of moment (MOM) has been studied to estimate the emitted electric field. However, the MOM is difficult to treat the dielectric material of the cable. This paper proposes the method of creating the wire grid model considering the dielectric material of the power line cable. The radius of the wire was determined from the per unit length inductance of the cable. The admittance is inserted between wires to present the effect of the dielectric material, and the value is determined from the admittance calculated by using the FEM based on the two-dimension model. The other admittance was inserted between each wire and ground and the value was also determined from the FEM results. The appliances were presented by T-type network based on the measurement results. The common mode input impedance and radiated magnetic field were measured and compared with the calculated one, and the evaluation indicated that the well agreement was obtained. A simple model of the indoor power line system was constructed and the radiated magnetic field was calculated. The evaluation was indicated that the calculation results almost agreed with the measured one. These results mean that the wire grid model is effective to estimate the radiated electromagnetic field from PLC system.

High-speed power line communication (PLC) systems have been developed for home networks. However, the transmission characteristics of an indoor AC mains line have not been clarified. We studied the influence of the appliance operation state on the transmission characteristics of the indoor AC mains line. The AC mains line and appliances were represented by four-port networks and two-port networks. The transmission characteristics were calculated by a model constructed with these networks. The two-port network parameters of the appliances were measured in both operating and stop states. The equivalent circuits were determined for both states based on the condition that the frequency characteristics of the circuits agreed with the measured value. A simple AC mains system was constructed and the transmission characteristics were measured to compare with the calculated value in various states. The results indicate that the calculated value agreed well with the measured one, and the transmission loss deviation resulting from the appliance state was within 10 dB. A common mode choke coil was inserted between the AC mains line and the appliances to reduce the transmission loss deviation resulting from different states. The measured and calculated values indicate that the deviation was reduced from 10 dB to 0.5 dB by inserting the filter.

Telecommunications signal emissions from unshielded twisted pair (UTP) cable should be suppressed to maintain EMC of telecommunication systems. This paper describes the suppression effects of the ferrite cores which are installed on the UTP cable. Twisted pair wire with ferrite core was modeled by 4-port network to evaluate suppression effect. Parameters of the networks which are constructed with UTP cable or ferrite core with wires were determined from calculation and measurement. Using the networks, the common-mode current distribution on the cable was obtained, and emitted electric field strength was calculated from the distribution. The emission suppression effect was obtained from the result, and the results were almost agreed with measured value. The calculation results suggest that 1) the ferrite cores should be arranged side by side, 2) these should be placed near the signal supply end of the cable., 2003 IEEE Symposium on Electromagnetic Compatibility, August 18-22, 2003, Boston, MA, USA

A method of evaluating the isolation factor from an AC mains port to a telecommunication port was investigated. Telecommunication equipment was represented by a 4-port network consisting of a pair of wire and ground. The relationship between input and output signals of the network was represented by an F-matrix and the isolation factor (ratio of input to output signals) was derived from the matrix. We developed a method of measuring the parameters and the measured values for a resistance-network agree well with calculated ones. The evaluation results of the isolation factor for three types of telecommunication equipment show that isolation for differential-mode noise from AC mains to telecommunication ports is larger than that for common-mode noise., 2003 IEEE Symposium on Electromagnetic Compatibility, August 18-22, 2003, Boston

Spherical dipole antenna has been used to evaluate EMC performance because it can consider small dipole source. In this paper, site attenuation of spherical dipole antenna is calculated using wire grid model. It is also measured in semi-anechoic chamber for 3m distance, and the result indicates the deviation between calculation and measurement result is within 4dB from 30 MHz to 1000 MHz. The site attenuation distribution is measured in a small semi-anechoic chamber and compared with the measured one. The result indicates that the large reflection loss absorber is effective to improve the performance of the site and the site attenuation is improved when transmitting and receiving antenna place at line unsymmetrical position.

Grounding search systems need improved sensitivity to search more effectively for grounding routes. The proposed method changes the phase reference signal source from the search signal to a TV signal. A minimum signal level of 17 dBuV at the antenna terminal is needed to obtain the phase reference. Experimentation using the new system demonstrated an improvement of 40 dB in the minimum detectable level and the phase measurement deviation improved from ±18 degrees to ±8 degrees., 1999 International Symposium on Electromagnetic Compatibility, May 17-21, 1999, Surugadai Memorial Hall, Chuo University, Tokyo, Japan

Lightning surges in a telecommunication building were observed before and after installing a dissipation array system (DAS) for lightning in winter. A portable digitizing oscilloscope and a multichannel digitizing oscilloscope with an optical fiber system were used for the observation. The observed results from winter 1991 to winter 1996 show that the peak value occurrence probability at an antenna tower leg was not changed before and after installing the DAS and the occurrence at a pillar of the building was decreased a bit by installing the DAS. The peak value of the lightning current at the lightning rod of the building was estimated from the surges observed at the lightning rods, at a leg of each telecommunication tower, and at a building pillar. The occurrence calculated from this value was almost the same before and after installing the DAS., 1998 International Symposium on Electromagnetic Compatibility, 24-28 August, 1998, Denver, CO, USA

This paper describes a method of improving the frequency response of an electric field sensor. A modified LiNbO/sub 3/ substrate shape reduces the sensitivity deviation from 4 [dB] to 1 [dB] and the maximum operating frequency is raised from 300 [MHz] to 1 [GHz] by using a resistive loaded element., 1994 IEEE Instrumentation and Measurement Technology Conference, May 10-12, 1994, Grand Hotel Hamamatsu, Hamamatsu, Japan

This paper describes experimental and analytical results of electromagnetics pulses caused by electrostatic discharge (ESD). Energy spectra of ESD pulses measured by plural antennas are analyzed for three frequency domains (1-30MHz, 30-200MHz, 200-750MHz). Analytical results show that ESD energy does not always increase in proportion to discharge voltages and that ESD pulses produced by low voltage ESD may cause strong electromagnetic interference., IEEE 1992 International Symposium on Electromagnetic Compatibility, August 17-21, 1992, Anaheim, California

A Mach-Zehnder interferometer whose half-wave voltage is about 4 V and a YAG laser pumped by a laser diode whose output power is 25 mW are used to improve the sensitivity of a LiNbO/sub 3/ electromagnetic field sensor. The resulting frequency response is almost flat from 100 Hz to 300 MHz and the minimum detectable electric field strength is 1 mV/m at 50 MHz and 0.14 mV/m at 750 MHz. The frequency response of the sensor is analyzed using the moment method, and the calculated results agree with the measured results. The improved sensor can measure an electromagnetic impulse whose peak value is larger than 10 V/m and width is wider than 5 ns., 1991 IEEE International Symposium on Electromagnetic Compatibility, 12 July-16 August, 1991, Cherry Hill, NJ, USA

This paper describes the propagation characteristics of electromagnetic pulses induced by electrostatic discharge (ESD) in the far field. ESD energy spectra measured with an electric field sensor using a Mach-Zehnder interferometer are analyzed for the frequency band DC-1 GHz by short-time Fourier transform (STFT). Analytical results show that ESD energy in high frequency band (100 MHz-1 GHz) decrease more rapidly in proportion to the distance from a source point., 1999 International Symposium on Electromagnetic Compatibility, May 17-21, 1999, Surugadai Memorial Hall, Chuo University, Tokyo, Japan