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40 GHz and 70 GHz Launch DifferencesThe launch design will have its own frequency range limitation. The sizing and spacing launch geometry is proportional to the wavelength of the energy that is traveling through the transition. Having the smaller geometry is a challenge to the limitations of board fabrication processes and leads more inconsistency in the performance of the high frequency boards after fabrication. The lower frequency boards are not as sensitive to the variations inherent in board processing and perform more consistently between individual boards after fabrication.On the left are 40 GHz and 70 GHz bandwidth grounded coplanar waveguide (GCPW) and microstrip test boards. These are standard Signal Microwave test boards made using 8mil thick Rogers RO4003 material with an FR-4 stiffener.Shown in the close-ups are comparisons of the 40 GHz launch designs and 70GHz launch designs. The 70 GHz launch has different size vias, notably the first vias on either side of the trace, and they are spaced closer to the trace and the edge of the board. The 40GHz launch designs have larger vias and are not spaced as tight.
40GHz和70GHz发射差发射设计会有自己的频率范围限制。发射几何形状的尺寸和间距与穿越跃迁的能量波长成正比。拥有更小的几何形状是对电路板制造工艺限制的挑战，并导致制造后高频板的性能更加不一致。低频板对板加工中固有的变化不那么敏感，并且在制造后各个板之间的性能更加一致。左边是40 GHz和70 GHz带宽接地共面波导(GCPW)和微带测试板。这些都是标准的Signal Microwave测试板，采用8mil厚的Rogers RO4003材料，带有FR-4加强筋。特写中显示的是40GHz发射设计和70千兆赫发射设计的比较。70 GHz发射具有不同尺寸的过孔，特别是在走线两侧的第一个过孔，它们的间隔更靠近走线和电路板边缘。40GHz发射设计的过孔更大，间隔也没有那么紧。
Top Ground Launch for Multi-Layer BoardsTop Ground LaunchFor both microstrip and GCPW transmission lines, when implemented in a multi-layer board configuration, the ground layer for the microwave transmission line is buried. The connector will not have access to it no matter how the connector is configured.The launch designs developed by Signal Microwave incorporate a short section to transition the ground connection from the top of the board to the buried ground layer.The small set of vias at the edge of the microstrip board is a GCPW section used to transfer the energy from the connector to the board using only the top ground connection of the connector.Signal Microwave Board ConstructionThe 8 mil RO4003 top layer is processed seperately including vias and plating. Then the RO4003 layer is laminated to the FR-4 layer which acts as a stiffener. The FR-4 layer does not have through vias that can cause resonances and no back drilling is required多层板的地面发射地面顶发射对于微带和GCPW传输线，当在多层板配置中实现时，微波传输线的接地层是埋置的。无论连接器如何配置，连接器都无法访问它。由信号微波公司开发的发射设计包括一个短的部分，将地面连接从板的顶部过渡到埋地层。微带板边缘的一小组通孔是GCPW部分，用于仅使用连接器的顶部接地连接将能量从连接器转移到板上。信号微波板结构8 mil RO4003顶层分别处理，包括过孔和电镀。然后将RO4003层与FR-4层叠合，作为加强层。FR-4层没有可能引起共振的通孔，也不需要回钻
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