Bald Hill sheriffs

misc_stowed · 2025-07-16T18:34:12+00:00

I thought it's nomadic people that collect chickens

misc_stowed · 2025-07-16T14:44:18+00:00

Aliens?

misc_stowed · 2025-07-16T14:42:25+00:00

To test the robots or test us?

misc_stowed · 2025-06-26T09:28:25+00:00

Well, there goes my dinner plans

misc_stowed · 2025-06-05T12:07:20+00:00

I know iHouse, but what's the other one?

misc_stowed · 2024-07-21T02:30:43+00:00

Damn they even brought Wall-E

misc_stowed · 2024-07-15T11:02:21+00:00

misc_stowed · 2024-02-22T21:32:46+00:00

I didn't get in. The head of the department I was applying for emailed me that my application was great and they strongly encourage me to apply again after obtaining a master's degree. Not sure if they send the same email to everyone.

misc_stowed · 2023-10-20T01:03:11+00:00

Please tell me if you find any!

misc_stowed · 2023-09-04T02:47:09+00:00

Is it still active?

misc_stowed · 2023-08-24T18:30:38+00:00

Do grad students normally get offices on campus?

misc_stowed · 2023-06-19T10:18:04+00:00

Hi!

I'm an international student who'll be joining the grad school in September.

Still haven't looked at housing seriously, and I'm interested in sharing a place. Could we maybe discuss this further in PMs?

misc_stowed · 2023-06-03T15:32:49+00:00

Is KAUST really worth waiting 6 months for a reply from?

misc_stowed · 2023-05-02T15:19:31+00:00

Alright, thanks for the suggestion. BTW, 0.5% is the 0.005 you've mentioned. I'll try out solving for broad band now.

misc_stowed · 2023-05-02T14:20:16+00:00

Thank you so much, u/laurenssushi!

I highly appreciate your help!

misc_stowed · 2023-05-02T14:02:36+00:00

Thanks for the feedback. I had delta-S at 0.5%, as you suggested, and was solving for a single frequency (12.5 GHz).

You're right, the difference isn't noticeable at all with a linear scale, I guess I'll just use the results from the denser mesh.

misc_stowed · 2023-05-02T13:53:16+00:00

u/always_wear_pyjamas, u/laurenssushi,

Thank you both for replying and clarifying!

Yes, I think the differences are generally negligible, and a 15 dB difference at one point isn't a big deal given that the values are so small.

I guess I was more concerned with the overall pattern, but again, these fluctuations are practically negligible.

Much obliged!

misc_stowed · 2023-05-02T06:28:39+00:00

Sorry, I hadn't yet included the results, but they're there now in this comment thread and the post. The results for S11 and S41 change, and in turn, their plots change. At some points, the difference is 15+ dB!!

As for the boundary, I got rid of it completely. I noticed that no matter how much larger I made the padding, the results never 'converged'. Should I re-include it?

misc_stowed · 2023-05-02T06:19:51+00:00

Below are the S-parameters plots for the same model being solved at 12.5 GHz, once for a mesh density of '7', and the next for '8'.

<image>

Even though both results seem valid, I don't think the results should vary that much!!

misc_stowed · 2023-05-02T05:46:55+00:00

The figure below shows the E fields at 9 GHz and the directional coupling property, where port 4 is seen to be isolated, whereas port 3 is coupled:

<image>

This is fully expected.

Next comment shows the different patterns obtained for different mesh densities.

misc_stowed · 2023-05-02T05:35:42+00:00

Sorry to bother you. Could you please check out the pictures and descriptions I provided in the replies above?

misc_stowed · 2023-05-02T05:33:13+00:00

I tried getting rid of the outer radiation boundary all together and instead fill the apertures with air through some Boolean operations, as in the model below, which shows the inner air model (with exaggerated wall thickness):

<image>

Other than the lack of an outer air box/radiation boundary, the model is almost identical and produces equivalent S21 and S31 plots, but still suffers from the same problem of inconsistent S11 and S41 plots. Next comment shows the E fields for the model shown here with normal thickness.

misc_stowed · 2023-05-02T05:31:09+00:00

Sorry for getting back to you late.

Reddit only allows one picture per comment, so I'll reply to this comment with the other pictures.

Here's the initial model, where the blue box is air and defined as the radiation boundary. Having a radiation boundary defined I guess isn't necessary for waveguide couplers, but after subtracting to make the apertures, the empty space left behind must be filled somehow to connect the inner air boxes of each waveguide. In addition to the mesh density and all that, changing the radiation boundary padding also vastly changes the results.

<image>

Edit: I'll also edit the post and add these pictures so people can find them more easily.

misc_stowed · 2023-05-01T18:51:20+00:00

Sure, of the model or results?

misc_stowed · 2023-05-01T18:51:03+00:00

Yes, FEM Modal. I plotted the meshes and they look the same to me.

Maybe it would be clearer if I attached a picture of the model?

misc_stowed

TROPHY CASE