I've been looking at some reference designs to guide my own design recently, and I noticed some possible discrepancies on one in particular.
This is the reference design:
http://www.ti.com/tool/TIDA-00848?keyMatch=cc1310&tisearch=tidesigns (page and design files)
In section 9.3 it states the feed line was modified to be 50-ohms with the 1mm thick PCB. The design files show a microstrip line width of 24 mils and a spacing of 6 mils from the ground plane on each side. However, doing the maths on these figures as a co-planar waveguide (with Saturn PCB toolkit) the impedance actually comes out more like 56-Ohms.
Is this correct? And if so, is it just a case of the feed line being so short they don't mind it's a bit mismatched?
If it's not correct, how was it calculated? By my calculations the feed line would have to be about 33 mils wide to have the correct impedance.