PCB新聞 - 阻抗的主要類型及影響因素

阻抗（Zo）定義：在已知頻率下流過的交流電的總電阻稱為阻抗（Zo）。 對於印刷電路板，它是指某個電路層（訊號層）在高頻訊號下到其最近基準面的總阻抗。

2.1 Impedance type:
(1) Characteristic impedance. 在電腦和無線通訊等電子資訊產品中, 傳輸的能量 PCB電路 is a square wave signal (called pulse) composed of voltage 和 time. 遇到的電阻稱為特性阻抗.
(2) Differential impedance Two identical signal waveforms with opposite polarities are input at the driving end, 分別由兩條差分線路傳輸, 兩個差分訊號在接收端相减. 差分阻抗是兩條導線之間的阻抗Zdiff.
(3) Odd Mode Impedance The impedance value of one line to the ground of the two lines is the same as the impedance value of the two lines.
(4) Even mode impedance drive terminal input two same signal waveforms with the same polarity, 兩條導線連接在一起時的阻抗Zcom.
(5) Common mode impedance the impedance Zoe of one of the two lines to the ground, 兩條線路的阻抗值相同, 通常大於奇模阻抗.
其中, 特性阻抗和微分阻抗是常見的阻抗, 共模和奇模是罕見的.
2.2 Factors affecting impedance:
W---line width/行間線寬新增, 阻抗降低, and the distance increases the impedance increases;
H-Insulation thickness increases in thickness and impedance increases;
T-copper thickness copper thickness increases and impedance decreases;
H1-green oil thick the thickness increases and the impedance decreases;
Er-the dielectric constant "reference layer" DK value increases, the impedance decreases;
Undercut-W1-W Undercut increases, 阻抗變大.

以上介紹了阻抗的主要類型和影響因素. Ipcb也提供給 PCB製造商 and PCB製造 科技.