microstrip via fence intuition question

[yefj]

Hello,I want to add a VIA fence to improve the signal of the microstrip shown below. I know that the distance between vias (brown arrow) is lambda/20.
1.what via diameter to use?
2.What the the vertical distance (blue arrow) between the VIAS?

3.If i will put a field monitor on the VIA fence how can i see from the electric field that the VIA fense is working well? Thanks.

 

[volker@muehlhaus]

Your grounded via fence will change capacitance to ground -> change line impedance if it is too close.

At a distance of 3x line width or 3x substrate height, that effect should be negligible. But of course, you can also place the via fence closer if line width calculation includes the via fence effect.

 

[FvM]

Alternatively you can change the transmission line from micro strip to coplanar waveguide with ground.