Agilent Advanced Design System model of an avalanche transistor pulser

• Stato: Closed
• Premio: $281
• Proposte ricevute: 6
• Vincitore: scieng

Winner

Descrizione del concorso

I am looking for an experienced engineer who can create an Agilent Advanced Design System model of an avalanche transistor pulse generator.

I am teaching my students about effects such as reflections from impedance discontinuities, propagation time, dispersion etc through a combination of experimental work and modelling. To support the course I am creating, I would like to have a transient model of Jim Williams' famous avalanche transistor-based pulse generator that was published in Analog Device's application note AN47.

I am NOT after a simple pSpice/LTspice model - these are trivial to make using spice models of transistors available for download. I need a model that incorporates real transmission line/geometric effects and can fuse electromagnetic models with non-linear TRANSIENT circuit simulation such as Agilent's Advanced Design System.

Our university uses (ancient) ADS 2011 software in the student laboratories, so compatibility with this version would be appreciated, but is not strictly essential - if I can have a working cross domain simulation I will beg/borrow the necessary software.

I've attached files to this project description illustrating the sort of design I'm expecting, but be aware that my own ADS skills are relatively limited, so use them for inspiration only. Please do whatever you need to make your simulation work! I expect you'll need to integrate a pSpice model into the design somewhere, and assemble a plausible microstrip layout encapsulating the effects of the transmission line distributed capacitance and series inductances into the circuit. We will be using the FMMT415 and FMMT417 avalanche transistors. I've included the spice model available from download from Diodes Inc. Please use these in your circuit model.

So, in summary, I need:

* An ADS (or similar CROSS domain -i.e. hybrid electromagnetic AND non-linear circuit simulator) model of an avalanche transistor pulse generator.
* Ability to simulate a transient/TIME-DOMAIN output. A successful simulation will display the relaxation oscillator behaviour exhibited by a real device and demonstrate changes of pulse width etc. achieved through varying transmission line lengths and circuit geometry.

Again, I DO NOT want just a Spice model.

Footnote: While ADS is the preferred simulation platform for compatibility, if anyone can demonstrate a convincing solution implemented in something else (e.g. CST, Feko, Sonnet, OpenEMS etc, I'm still interested. Let me know :)

Competenze consigliate

• Analog Electronics
• Electronic Design
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• Simulation