Murata SWF accuracy and PCB layout question

Question

Hi guys. I was observing the PCA10121 PCB layout using this link. 
 Schematic for PCA10121 nRF5340 Audio DK 
 
 From Murata SWF connector datasheet, it says 
 https://www.murata.com/-/media/webrenewal/support/library/catalog/products/connector/o30e.ashx?la=en-gb&cvid=20220210015534000000 
 Connector performance is influenced by GND among inner layers of substrate. 
 We recommend making space more than 0.4mm between connectors and GND.

In case of PCA10121, to follow Murata's 400um keepout rule, which layers are removed under J1 (MM8130-2600)? Is it 
 Dielectric 1 + Mid layer 1 + Dielectric 2 + Mid layer 2 = total 212um? OR 
 Dielectric 1 + Mid layer 1 + Dielectric 2 + Mid layer 2 + Dielectric 3 = total 1212um? 
 
 Also, under J1, the Top layer GND can be kept, right? 
 
 Lastly, SWF datasheet doesn't show the insertion loss after 6 GHz. 
 Is the SWF or SWG reliable when measuring 2nd, 3rd, 4th, ... harmonics? I know one Nordic Thread recommended UFL connectors 
 SWF connector for customized PCB 
 but I would like to use SWF due to the convenient feature of this connector so I'd like to hear your tips and what accuracy were observed. 
 
 Thank you so much!

JONATHAN LL · Accepted Answer

Hi, So did some quick tests just to see if there was much of a difference and provide some numbers. Adding a power point with the plots, only for channel 40 with +4dBm. I did not adjust for the difference in loss with the two connection types, but a quick comparison between the delta variation of each "connector" seem to show that they perform about the same. Wit the setup we use when we do tuning on customer products. SWF connecotr VS Coaxial probe.pptx The coaxial probe was connected to the same pad that the SWF connector is connected to, so physically on the PCB the connectors where on the same location. So for testing and inspecting it is ok, but for official certification high accuracy measurements then I would go for a connector that is rated for the task specifically. I can do some more if you have anything specific in mind. Regards, Jonathan

Murata SWF accuracy and PCB layout question

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