Hidden antenna currents in domestic power-line network : Mode conversion at switch branch

オクナイ　デンリョク　ハイセン　ニ　オケル　カクレタ　アンテナ　デンリュウ　スイッチ　ブンキ　ニ　オケル　モード　ヘンカン

キタガワ, マサヒロ

Kitagawa, Masahiro

漏洩電磁界

スイッチ分岐

アンテナ電流

コモンモード

モード変換

直列ショートスタブ

LCL

power line communications (PLC)

radiated emission

switch branch

antenna current

common mode

mode conversion

series closed stub

The common-mode (CM) current generated from the differential-mode (DM) signal at the unbalanced elements distributed on the power-line network is the origin of the radiated emission from the power-line communications (PLC). The LCL measured at the outlet is often used as a measure of the unbalance in power-line. However not all CM currents generated appear at the outlets. In this Paper, we have analyzed the mode conversion at the swich branch which consists of the ceiling light and the wall swith, forms one-leg serial stub, and is typical unbalanced elements on the domestic power-line. We have proved the existance of the hidden antenna current under more general condition than folded dipole. The hidden antenna currents contribute to the radiated emission but not to the CM current or the LCL measured at the outlet. Therefore the outlet LCL is ovbiously not good measure of radiated emission. Taking the hidden antenna currents at the switch-branch into account, the lowest LCL of the swich-branch becomes -6dB. Taking the DM loss between the outlet and the switch-branch into account, the effective (minimum) LCL is around 0dB.