Introduction To Remote and Distributed EM Simulation

As designs are becoming more and more compact, EM simulation is becoming more prevalent not just for design verification, but also is being used in the design/redesign cycle.  Shape modifiers make parameterizing existing artwork easy so designs can be easily modified to meet new specifications. 

Simulating EM structures on your local machine works great for smaller, faster, structures, but what happens when your structure begins to take a markedly long time; all the while typing up your local resources so it's cumbersome to continue working on your local machine?

What if a structure requires too much memory to simulate on your local machine?

Or perhaps you have a design of experiments you'd like to run, but simulating them serially would take too long?

The AWR Design Environment remote simulation capability addresses these common concerns.  Before we begin discussing the capability, let's define some terminology:

• Client Machine - Computer where the user is designing in AWR.
• Remote Simulation - Simulation on a machine other than the client.
• Distributed Simulation - Simulation on more than one machine, simultaneously.

Remote/Distributed Example

Open the project and follow the steps below.

Note: The initial simulation takes a moment as it's simulating ~50,000 points.

To show the benefits of remote/distributed simulation we've used shape modifiers on an existing output matching network of an amplifier to tune in the performance of the device to a specified efficiency and output power.  A total of 625 unique output matching networks were simulated in AXIEM with three different sets of computational resources; the local workstation, a single remote simulation server that has higher performance than the local workstation, and six identical remote simulation servers so that the geometry sweeps can be run in parallel.  A summary of the benefits of running the simulation on the faster remote machine and distributing the simulations across multiple, faster, remote machines is below.  

What is Simulating?

The output matching network is a three section stepped impedance matching network.  Shape modifiers are used to increase/decrease the length and width of the first two sections of the matching network.  A total of 625 unique EM structures were simulated to explore this design space.

The target impedance is a specified region on the Smith chart representing an area where this device achieves a certain output power and efficiency.  It's important to note the Smith chart is a 4 Ohm smith chart, giving us a larger picture of the goal and matching network impedance.

Remote Simulation Benefits

Simulation of these 625 EM structures took about 10 hours on the local machine.  Simulating remotely on a single, faster, machine reduces that time by >2X, all the while not tying up resources on the local workstation for 10 hours.

Distributed Simulation Benefits

When the same 625 EM structures were remotely simulated and distributed across 6 identical machines, the total simulation time was cut down by >10X. A simulation that would have occupied the local machine for an entire work day is now completed in less than half an hour.

Interpolating in the Design Space

The sweeps of the EM structure were pre-defined and simulated giving us a dataset containing the results for every combination of geometry modification.  This allows interpolation between the simulation points and fine tuning of the matching network without having had simulated every point. 

Note:  The EM structure sweep step sizes are 40 mils but the tuning steps are in 10 mil increments.

Verification

Once the EM structure was tuned in to meet the efficiency and output power specifications, the circuit performance can be verified against the goals.

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