基于电磁带隙结构的 CCD 相机成像电路降噪

摘要

文章研究了几种不同形式的电磁带隙（electromagnetic band-gap, EBG）结构，并分析了平面 EBG 结构的等效电路，提出一种适用于高速模数混合电路的平面 EBG 结构，可有效抑制电路中的同步开关噪声。使用 ANSYS HFSS 仿真软件对该 EBG 结构的频域特性进行了分析，结果显示：当抑制深度为–30dB 时，阻带范围为0.7~2.3GHz 和3.0~10GHz。相对于传统 EBG 结构，其阻带带宽由7GHz 增加到8.6GHz。文章根据一款实用的 CCD 相机成像电路的 PCB 尺寸、噪声干扰源和敏感端的位置布局等信息，对其进行仿真分析，发现在使用改型 EBG 结构时，电路中的同步开关噪声得到一定抑制，为 EBG结构在 CCD 相机成像电路中的应用提供了参考。%By study of different structures of electromagnetic band-gap(EBG)and analysis of equivalent circuits of several planar EBG structures, a novel planar EBG structure is proposed for simultaneous switching noise(SSN)suppression in high speed mixed-signal processing circuits.With simulations of the EBG structure in frequency domain by ANSYS HFSS, the results show that a suppression depth of –30dB and two stop-bands of 0.7~2.3GHz and 3~10 GHz are obtained. Compared with traditional EBG structures, the total stop-band bandwidth increases from 7GHz to 8.6GHz, rising by 20%. Furthermore, based on size of a practical PCB in CCD camera imaging circuits and the position of interference sources and sensitive ends, the PCB with novel planar EBG structure has a better SSN suppression performance in high speed circuits through comparative simulation and analysis. This lays a foundation for using EBG structure in practical circuits.