抑制同步开关噪声的新颖电磁带隙结构

A Novel Electromagnetic Band-Gap Structure for Noise Suppression of Simultaneous Switching

为了抑制印刷电路板的同步开关噪声(SSN),提出了一种新型二维电磁带隙结构.基于金属折线增强相邻单位晶格间的电感,采用折线与含有缝隙的正方形金属贴片桥接构建单位晶格,实现新型电磁带隙结构设计.应用HFSS软件仿真分析电磁带隙结构,结果表明:与相同参数的L形桥接电磁带隙结构比较,抑制深度为-30dB时,阻带带宽为0.45～5.3GHz,相对带宽提高了约15%,阻带下限截止频率下降了150MHz.测量结果与仿真结果吻合,能够全向抑制电源平面上的SSN,同时采用差分线对传输信号时,对信号完整性造成的影响较小.

A novel planar electromagnetic band-gap （EBG） structure is proposed to suppress the simultaneous switching noise （SSN） within the power/ground planes of the printed circuit boards. The novel design bases on the facts that meander lines increase the effective inductance of EBG patches, and that the unit cell of the EBG power plane consists of one square patch with the slots and four meander line bridges. The proposed design is validated by HFSS numerically, and comparisons with the L-bridged EBG of the same parameters, under the conditions with the --30 dB suppression and bandwidth ranging from 0.45 GHz to 5.3 GHz show that the lower cut- off frequency is decreased by 150 MHz, and the relative bandwidth is increased by about 15%. The proposed EBG power plane is fabricated and measured, and good agreement between the simulated and measured results is found along with the omni-directional suppression of the SSN. It is also found that good signal integrity performance can be obtained when differential transmission lines are used.