本帖最后由 herosyfj 于 2013-10-13 11:29 编辑
CSR8600硬件设计向导 CSR8600 HW Design Guidelines.pdf中的一段话话，如下：
The track from the filter to the antenna has been designed as a coplanar waveguide with ground. The ground plane on layer 2 has been removed from underneath the track and a ground plane on layer 3 is used. This increases the distance between the track and ground plane to about 1.27 mm, which means a much wider track of 0.56 mm with a 0.1 mm gap can be used to give the same 50 Ω impedance. The wider track provides better impedance matching at solder pad interfaces and provides better immunity to PCB manufacturing process variations.
本人试译如下，如有不对之处还请大侠指点！
滤波器到天线的线被设计为 和地的共面波导。PCB第2层(地层)在该线下面的地层被移除，使用第3层的的地。该线和地面之间的距离增加到大约1.27毫米,这意味着一个更宽的线(0.56毫米和0.1毫米的缺口)可以用，以取得相同的50Ω阻抗。更宽的线在焊盘接口提供更好的阻抗匹配、为PCB柔性加工过程提供更好的豁免权。
谢谢！
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发表于 2013-10-13 11:14:12
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