HFSS lumped port not equivalent to lumped RLC boundary condition

Hi,

I have a design with 2 waveports and 1 lumped RLC surface that simulates a capacitor. I have changed the RLC surface into a lumped port to have a 3x3 Z matrix, this way I can change the values of the lumped capacitor in post processing and reduce the 3x3 matrix down to a 2x2 matrix :

V1 = Z11*I1 + Z12*I2 + Z13*I3;
V2 = Z21*I1 + Z22*I2 + Z23*I3; + V3 * (1i*2*pi*C) = I3 -> V1 = Z11' *I1 + Z12' *I2;
V3 = Z31*I1 + Z32*I2 + Z33*I3; V2 = Z21' *I1 + Z22' *I2;


The problem is that I get different results when I simulate the project with lumped RLC than when I simulate the project with a lumped port and I reduce the Z matrix in post-processing (matlab). Anybody know what am I doing wrong?

Thanks

Hi morskie_oko,

This may just be a typo, but (1i*2*pi*C) does not equate to an impedance. I assume that you're only doing this at one frequency?

Hi PlanarMetamaterials,

indeed, it is a typo, I meant (1i*2*pi*f*C).

It looks correct, can you provide a picture so that I can make sure I understand your setup?