Hello,

I picked up an ADS lowpass filter schematic from another designer. The lowpass uses lumped element coils and is placed in a housing. The original designer placed some mutual coupling elements between the inductors to tweak the response.

I am interested in calculating the power dissipated in the inductors. If I disable the mutual coupling, the calculated dissipations look reasonable (relatively light coupling--disablingminimally effect the response). However, with the mutual coupling elements enabled, the power dissipated among the inductors (four inductors in my case) are significantly different and in some cases negative. However, if you sum the power among the four inductors (with mutual enabled), the total power dissipation looks reasonable.

So, my question(s): Why does the power dissipation distribution change so radically when adding the mutual coupling. [Power is calculated as 0.5*real(V x I*) and it is calculated into the device and out of the device--the difference being Pdiss]. Does this mean that the coupling terms are physically wrong or the inductor dots in the wrong direction? Or, does something get messed up in the matrix when mutuals are enabled such that the power dissipated becomes confounded? Is there a more generalized formulation for calculating dissipated power?

Thanks

Chard

I picked up an ADS lowpass filter schematic from another designer. The lowpass uses lumped element coils and is placed in a housing. The original designer placed some mutual coupling elements between the inductors to tweak the response.

I am interested in calculating the power dissipated in the inductors. If I disable the mutual coupling, the calculated dissipations look reasonable (relatively light coupling--disablingminimally effect the response). However, with the mutual coupling elements enabled, the power dissipated among the inductors (four inductors in my case) are significantly different and in some cases negative. However, if you sum the power among the four inductors (with mutual enabled), the total power dissipation looks reasonable.

So, my question(s): Why does the power dissipation distribution change so radically when adding the mutual coupling. [Power is calculated as 0.5*real(V x I*) and it is calculated into the device and out of the device--the difference being Pdiss]. Does this mean that the coupling terms are physically wrong or the inductor dots in the wrong direction? Or, does something get messed up in the matrix when mutuals are enabled such that the power dissipated becomes confounded? Is there a more generalized formulation for calculating dissipated power?

Thanks

Chard

GENESYS not working as you expected is a question for the support team so I have moved this thread to the Product Questions forum.

Real power is only dissipated in the real part of the inductor impedance, so you need to make sure you're modelling the unloaded Q in the coupled inductor model. I'm sure support will want a copy of your workspace so you might as well go ahead and attach it.

Clear skies and high Q.