Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

CST MWS 2014 - Lumped Element Anomaly between Frequency and Transient Solver

Not open for further replies.


Newbie level 2
Apr 13, 2015
Reaction score
Trophy points
Activity points
Hi All

Would somebody be able to help answer the following question:

I use here a simple square loop in MWS layout window to illustrate the problem. With a port placed in a gap in loop and snapped to corners of structure, I see a imaginary impedance of ~ 180 Ohms @ 2.4 GHz. This corresponds well with a first order approximation of the loop inductance calculated by hand. The real part is ~ 0.5 Ohm using PEC (perhaps leave that for latter!). So I now add a second gap in the loop and add a lumped element comprising 0.3 pF to provide a series resonance in the loop. Using the frequency domain solution I see the phase go too ~0 degrees @ 2.4 GHz which is correct. However using the transient simulation it does not!!!

So now I change the capacitor to a 0 Ohm resistor as this should make the impedance ~ 180 Ohms again using frequency solver which it does, but in transient I get O Ohm.

My suspicion is that there is a grid problem, but I intentionally snapped to corners to avoid this problem.

So my question is does anybody understand this problem between using frequency domain solver and transient ?

Many thanks, Munchie

Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com