How to calculate microstrip gap capacitance?

I read that if gap is large, then effect of capacitor can be ignored. But to understand quantities i want to know approximate capacitance depending on gap size. For example, for 50Ohm line with gap size of 0.1, 0.2, 0.3 mm etc.. I found something for coupled lines, but it is unclear how to use it for simplier gap

In AWR, you can set the gap and simulated the different gaps and then you can reduct the cap capcitance.

the formula for gaps was presented in many microstrip book by Bahl and others

a proper model for a gap is a series capacitance, with shunt capacitances on either side. The shunt capacitances become important in some cases.