I've seen various "recommended" chamfers for 90 degree grounded coplanar and microstrip traces. For example, or .
Is there a "rule of thumb" for which type of chamber and which geometries work best for RF layout? For my case I'm interested in 3 to 12 GHz with a grounded coplanar waveguide conductor of 10 mils with 6.5 mil air gaps on a 6.6 mil thick Rogers 4350B substrate. But my case aside, are there rules of thumb that I can follow to ensure I have a constant 50 ohm impedance without resorting to 3D EM simulators like CST Microwave or HFSS?