RE: How to design the matching circuit from ANT1/2 to 50 ohm?

MartinBL — Mon, 08 Jan 2018 09:31:49 GMT

Hi,

The nRF51 series should have the GND layer at the bottom to get the optimal substrate thickness between the matching network and GND. Strictly speaking, it is possible to have GND in the the inner layers, but the thickness between the matching network and the GND layer will then be so small that the matching network shown in the Product Specification is useless. The reference design in the PS is designed for a substrate thickness of 1.6mm and designs with anything less than 0.8mm usually have to be retuned and you should expect a hit on maximum output power. When you are satisfied with your design there is not much left to do other than to measure the output power and spurious emissions and then tune your design according to your results.

Please have a look at this PCB guideline for more general tips and note that you can always send us your schematics and layout files for review (You can send your files in confidence in MyPage). We are also happy to help you out with tuning of your final design free of charge.