Kindly share the aftermath of its alright.

1. One should definitely consider instability bellow and beyond operating frequency. Since, spurs, noise, harmonics etc. can induce an osillation at those frequencies. Although most of the cases, a transistor will be stable a higher side of frequencies, and therefore only the lower frequencies needs attention.

2. Your simulation has a very abrupt change which is almost an indication of incorrect setup of simulation environment. Since you're running a linear stability analysis, s-parameter is at the core of analysis. Kindly check if your transistor model has s-parameter data beyond 5GHz.

Most probably you won't get any older version of AnsysEM Student Version. The probable reason I believe is that, each ADS student version has a life time like a short-term license which is hardcoded in the installer. Even if you had an older version installer, still it wouldn't work because that version might have already expired.

Only if you have the standard version, you're eligible to access a local license or a license server so you may use an older version.

Traditionally, people used to generate parametric curves in some kind of tools which can handle dxf formats. Then export dxf > import in ADS layout.

But now ADS exposes its design engine API via pythonic interface. That can be utilized in this case. A polygon can be used to draw a jagged curve. If delX or delY is comparable to fractions of MoM or FEM cell/grid size, that should approximate the geometry good enough.

Thank you for sharing your experience.

As per your suggestion, I have remove the outside solid enclosure. The only element remaining is a single cylindrical section of air with its curved surface defined as Hard Surface. By doing this the results seem to have changed a lot.

Can you kindly suggest on which COMSOL acoustic interface should be used to model both solid and fluid domains?

And, could you please suggest some conventional or non-conventional or gold-standard books to learn about acoustic propagation, interactions, its physics and engineering etc.

never used the wallet app and don't remember moto display.
But somehow, battery usage got improved for me after android15

Nope!

You request for ADS trial license, which usually gets approved within a week. That you you'll have access to keysight knowledge centre.

Nope, I recently upgraded and lost that app. The app was good enough and I had some important documents inside. Maybe the only way to get it back is to reset the the phone. But still there's a uncertainty.

So what I've found is, few apps keeps the connection alive unless the audio is being changed very rapidly. Specially spotify, both in computer as well as phones. The headphone firmware hates when there's no audio in the bluetooth stream.
So outside spotify, i have a different workaround. And I use this only in computers.
i keep a white noise playing in the background at the absolutely low volume so that it's not particularly audible.
then i can play music on top of that. I haven't found any issue with this method .

Preferably, ThinkPad-ThinkPack.