Question: How does Insight recommend routing the RF signal trace beneath the module? — eg. layer stackup? Geometry? Etc.
Answer: Please find below the link of the gerber files of our ISP1507-AX test board (available on our website). http://www.insightsip.com/fichiers_insightsip/pdf/ble/ISP1507/ISP1507_TB_Gerber.zip
On the bottom side, we have designed a RF trace where we can connect a SMA connector for conducted test. This was made for certification test. The test board is a 4 layers stack and the SMA line is a 50 ohms matching line. They have to respect the antenna keep-out zone in the case the antenna of the module is used. In other case, for external antenna, you can put traces on this area.