I've a 0402 footprint and i would like to evaluate the stray (mutual) capacitance between the two pads.
What i know are
l*m : pad size
w : thickness of the pads
d : distance between pad
h : distance between pad and GND layer.
Actually i'm a bit confused about how to evaluate this stray capacitance. How can i take into a account the fact that i've both air on one side and FR4 on the other?
The only formula i've found on internet is:
Can you give me further information about the calculation?
Thanks in advance for the consideration.