3D EM absorber simulation

I suspect you will need an EM solver like Analyst / Clarity, or at least AXIEM, to effectively model the effects of a lossy boundary like an absorber.

You could create a 3D EM Structure and then open its Enclosure node -- and then go to the Boundary Conditions Tab -- to set the way in which the structure's boundaries are terminated.  You can of course set them as Open or Perfect Conductor, but you can also set them to be a material which you specifically define in the Material Defs. tab of the STACKUP.

See screenshots below.

Thanks for the hint. Digesting materials available on the net it looks that solver like Analyst is capable to solve scattering on the structure problem, while others are tailored to something like a circuit. 

My ultimate goal is to simulate normal and oblique incidence of plane wave onto complex multilayered surface made of dielectrics, metal patches, and probably lumped varactors between them, kind of smart surface. I am confident there will be challenges to reach the final goal, so I restrict myself to simpler problem of single material layer absorber, for which I could have analytical solution to verify. 

So yes, there was good hint to start with EM solver and observe boundary conditions for enclosure. 

What makes me stuck, is how do I perform measurement of such kind of structure? Say, at this point I'd like to have S11 at air-surface boundary at normal incidence. How do I set up that measurement? It looks that they require a port, and port in turn requires metal to be attached to. How do I define that? How could I define either normal or oblique incidence? We are having really hard time learning the tool without relevant example. 

Thanks in advance.

The types of analysis you wish to do require a 3D EM solver, which (in the Cadence suite of tools) would be the Clarity 3D Workbench.  This is the tool you should be evaluating for this task.

AWRDE is primarily an RF/Microwave circuit / system simulator.  It will seamlessly operate with other Cadence tools such as the Clarity 3D Workbench, so that the results of these external solvers can be used with the circuit / system simulations you do in AWRDE.

Thank you for this hint too. I guess I need some reading in that direction to proceed. 

Well, I have spent couple days fighting through the interface with help of AI tools and whatever I do the last stop is defining the port. I have tried with Analyst, still available in my setup, with Clarity - I can produce layered substrate, define boundary conditions on side walls of the enclosure to make the wave TEM, but whatever I do - just can't add excitation port at the top of the enclosure. Would appreciate if someone share their example or recipe. In my current mood if I hear that's impossible to do might be a relief too.

Thanks.

For port addition in Clarity, you may check following link:

Article (20515591) Title: Port Overview: Clarity Layout Workbench and Clarity 3D Layout
URL: ask.cadence.com/.../article-viewer

You can try using the Analyst-MP application instead of through MWO.  In that program you can set up ports and run simulations without needing to start in MWO.  You would need specific Analyst-MP features in your license file, which I am assuming you have.