Transient analysis with two independent sources

[rfmw]

I'm trying to simulate approx. 50 transistors with 30 diodes (all spice models) and some transmission lines in a circuit with two independent (unsynchronized) sources. First is sinewave (2.5 GHz) and the second is pulse source (800 ps period, 0.15 ns rise and fall times).

Since I've been using Ansoft's Designer for all my high-frequency circuits I've decided to go first with Designer and not anyother SPICE simulatiors.

The problem that I'm experiencing is that a simulation takes a looooong time with the two sources in the circuit. Sadly to say that I haven't got a results with two sources till today on a 2 GHz AMD processor. My max time step in transient analysis is 100 ps, but i would like it to be 10 ps...

What are your experience with transient analysis with multiple sources and WHAT SPICE or other simulator are you using? I need a simulator with RF elements (microstrip lossy transmission lines, smith-chart-capability diagrams,....)

Help or advice wanted

 

[rfsystem]

Every spice doing time domain transient simulation approximate the TL with a discrete circuit. That is the only way to simulate circuits containing TLs. If you doinf frequency domain transient simulation there should be a common denominator frequency. This is 1.25GHz, so there should be no problem. I think that the maximum frequency setting for the TL model is wrong and result in to many elements in the equivalent circuit.

 

[mohsenruz]

I prefer Saber. It is faster than spice. however I am not sure about RF simulation with saber.