Hi guys. I just have a question regarding the warning that I'm getting from my momentum simulation. Basically I am trying to simulate an asymmetric stripline with the following stack:

GND

MSUB1 (Er,Thickness) 3.66,0.76mm

METAL stripline

MSUB2 (Er,Thickness) 3.54, 0.1mm

GND

For simplicity we can ignore the metal thickness. Now whenever I make my simulation, a stripline with line width of 0.17mm results in 50 ohm (at 12GHz), as displayed in my smith chart. However, I do get this warning everytime:

Mesh generation at 12.7GHz.

port 2 : mesher chose to use an analytical (approximating) formula

to estimate the wavelength it needs to determine the maximum cellsize.

Mesh generation finished

S-parameter simulation

WARNING :

Port Solver failed to compute propagation constant and characteristic

impedance. 50 Ohm default impedance will appear in Dataset.

WARNING :

The 2D port solver data is not available,

using default values (50 Ohm) for the transmission line parameters.

Solver selection: automated choice of direct solver

My question is, is my line width correct for a 50 ohm stripline (using the above substrate stack) given that I am getting this warning during my simulations? What do these warnings mean?

Appreciate help from you guys.

GND

MSUB1 (Er,Thickness) 3.66,0.76mm

METAL stripline

MSUB2 (Er,Thickness) 3.54, 0.1mm

GND

For simplicity we can ignore the metal thickness. Now whenever I make my simulation, a stripline with line width of 0.17mm results in 50 ohm (at 12GHz), as displayed in my smith chart. However, I do get this warning everytime:

Mesh generation at 12.7GHz.

port 2 : mesher chose to use an analytical (approximating) formula

to estimate the wavelength it needs to determine the maximum cellsize.

Mesh generation finished

S-parameter simulation

WARNING :

Port Solver failed to compute propagation constant and characteristic

impedance. 50 Ohm default impedance will appear in Dataset.

WARNING :

The 2D port solver data is not available,

using default values (50 Ohm) for the transmission line parameters.

Solver selection: automated choice of direct solver

My question is, is my line width correct for a 50 ohm stripline (using the above substrate stack) given that I am getting this warning during my simulations? What do these warnings mean?

Appreciate help from you guys.

Warning about 2D port is killed if you choose Momentum->Port Editor->(Internal or any type of 50 OHm port). Ideal model of port wrong in any cases.