Analysis and verification for errors of normalized site attenuation method below 30 MHz

Various electrical devices, which radiate electromagnetic Helds of frequency ranges below 30 MHz, such as wireless power transfer systems, wireless charging devices, and PDP TVs, have been widely developed and manufactured. These devices radiate the spurious emissions of low frequency bands, below 30 MHz, and could affect other devices. In response to this, IEC CISPR has been discussing and standardizing the measurement and validation methods below 30 MHz. In addition, researchers who attended the CISPR annual meeting suggested the normalized site attenuation (NSA) method. However, this method has several problems in terms of the antenna factors, antenna feeding point, NSA values, etc. We found the NSA values and antenna factors to be the most important problem when the test is repeatedly performed. We need to recalculate the NSA values according to exact antenna shape and where the antenna feed point is. Therefore, we recalculated and adopted new NSA values by using the NEC program. According to the site validation test results, the calculated site attenuation deviation is satisfied within 4 dB ranges.