<div style='margin: 16px 0px; padding: 0px; color: rgb(100, 100, 100); text-transform: none; line-height: 24px; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' align="left" .="word-wrap: break-word;"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" .="word-wrap: break-word; color: rgb(26, 26, 26);"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" .="word-wrap: break-word;"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" size="3" face="宋体" .="word-wrap: break-word;">所谓
覆铜，就是将柔性
电路板上闲置的空间作为基准面，然后用固体铜填充，这些铜区又称为灌铜。覆铜的意义在于，减小地线阻抗，提高抗干扰能力；降低压降，提高
电源效率；与地线相连，还可以减小环路面积。也出于让
PCB焊接时尽可能不变形的目的，大部分PCB 生产厂家也会要求PCB
设计者在PCB 的空旷区域填充铜皮或者网格状的地线，覆铜如果处理的不当，那将得不赏失，究竟覆铜是“利大于弊”还是“弊大于利”？<div style='margin: 16px 0px; padding: 0px; color: rgb(100, 100, 100); text-transform: none; line-height: 24px; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' align="center" .="word-wrap: break-word;"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" .="word-wrap: break-word; color: rgb(26, 26, 26);"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" .="word-wrap: break-word;"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" size="3" face="宋体" .="word-wrap: break-word;"><img style="margin: 0px auto; padding: 0px; border: currentColor; vertical-align: middle; display: block; word-wrap: break-word; max-width: 100%; box-sizing: border-box;" id="aimg_193729" src="http://bbs.cirmall.com/data/attachment/forum/201808/11/135925kz72q62d90v6v3dr.jpg.thumb.jpg" .="word-wrap: break-word; cursor: pointer;" initialized="true" inpost="1" file="data/attachment/forum/201808/11/135925kz72q62d90v6v3dr.jpg.thumb.jpg" zoomfile="data/attachment/forum/201808/11/135925kz72q62d90v6v3dr.jpg" aid="193729"><div style='margin: 16px 0px; padding: 0px; color: rgb(100, 100, 100); text-transform: none; line-height: 24px; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' align="left" .="word-wrap: break-word;"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" .="word-wrap: break-word; color: rgb(26, 26, 26);"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" .="word-wrap: break-word;"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" size="3" face="宋体" .="word-wrap: break-word;">大家都知道在高频情况下，印刷电路板上的
布线的分布电容会起作用，当长度大于噪声频率相应波长的1/20 时，就会产生天线效应，噪声就会通过布线向外发射，如果在PCB中存在不良接地的覆铜话，覆铜就成了传播噪音的工具，因此，在高频电路中，千万不要认为，把地线的某个地方接了地，这就是“地线”，一定要以小于λ/20 的间距，在布线上打过孔，与多层板的地平面“良好接地”。如果把覆铜处理恰当了，覆铜不仅具有加大电流，还起了屏蔽干扰的双重作用。<div style='margin: 16px 0px; padding: 0px; color: rgb(100, 100, 100); text-transform: none; line-height: 24px; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' align="left" .="word-wrap: break-word;"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" .="word-wrap: break-word; color: rgb(26, 26, 26);"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" .="word-wrap: break-word;"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" size="3" .="word-wrap: break-word;">
L~PBD?l <div style='margin: 16px 0px; padding: 0px; color: rgb(100, 100, 100); text-transform: none; line-height: 24px; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' align="left" .="word-wrap: break-word;"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" .="word-wrap: break-word; color: rgb(26, 26, 26);"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" .="word-wrap: break-word;"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" size="3" face="宋体" .="word-wrap: break-word;">覆铜一般有两种基本的方式，就是大面积的覆铜和网格铜，经常也有人问到，大面积覆铜好还是网格覆铜好，不好一概而论。为什么呢？大面积覆铜，具备了加大电流和屏蔽双重作用，但是大面积覆铜，如果过波峰焊时，板子就可能会翘起来，甚至会起泡。因此大面积覆铜，一般也会开几个槽，缓解铜箔起泡，单纯的网格覆铜主要还是屏蔽作用，加大电流的作用被降低了，从散热的角度说，网格有好处（它降低了铜的受热面）又起到了一定的电磁屏蔽的作用。<div style='margin: 16px 0px; padding: 0px; color: rgb(100, 100, 100); text-transform: none; line-height: 24px; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' align="left" .="word-wrap: break-word;"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" .="word-wrap: break-word; color: rgb(26, 26, 26);"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" .="word-wrap: break-word;"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" size="3" .="word-wrap: break-word;">
D%+cf <div style='margin: 16px 0px; padding: 0px; color: rgb(100, 100, 100); text-transform: none; line-height: 24px; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' align="left" .="word-wrap: break-word;"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" .="word-wrap: break-word; color: rgb(26, 26, 26);"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" .="word-wrap: break-word;"><font style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" size="3" face="宋体" .="word-wrap: break-word;">需要指出的是，网格是使由交错方向的
走线组成的，我们知道对于电路来说，走线的宽度对于电路板的工作频率是有其相应的“电长度“的（实际
尺寸除以工作频率对应的数字频率可得，具体可见相关书籍），当工作频率不是很高的时候，或许网格线的作用不是很明显，一旦电长度和工作频率匹配时，就非常糟糕了，你会发现电路根本就不能正常工作，到处都在发射干扰系统工作的信号。所以对于使用网格的同仁，我的建议是根据设计的电路板工作情况选择，不要死抱着一种东西不放。因此高频电路对抗干扰要求高的多用网格，低频电路有大电流的电路等
常用完整的铺铜。
