A study on measurement method of near electric field noise from LED bulbs

Although the inverter circuit is used to make high efficiency of LED bulbs, the large electromagnetic noise radiated from the inverter circuit may influence to the radio communication system. Though near magnetic field noise from LED bulbs was not detected, near electric field was detected. The purpose of this study is to propose the measurement method of near electric field noise from LED bulbs by using monopole antenna. The calibration factor is obtained by a near field three antenna method. Alternatively, using two different length antennas, 1 to 400 MHz wideband measurement can be possible to use. Actually, characteristic near electric field is observed from 100 to 200 MHz. This result conformed to far electric field from LED bulbs, and it has correlate with near electric field. The cause of the large electric field radiation is the resonance power line.