I am simulating differential via having cases of back-drilling and without back-drill in order to observe impedance discontinuity. I selected the required 3D area and exported in 3D solver and observed return and insertion loss, while doing back-drill return loss should decrease return loss is increasing in my case while i am doing backdrilling. I think i am lagging in port assignments initially while exporting it asked for port for lower reference and upper reference, I assigned it as lower reference.
Can anyone help me in assignment of ports properly.
Regarding port assignment there is no difference between backdrilled and not backdrilled. Does the via barrel length really reflect your intention to look at backdrilled and not backdrilled scenario? Do you want to discuss this off line? Please mail me at email@example.com.