Lecture -- Coupled-Mode Theory and Devices
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- Опубликовано: 25 май 2024
- This short video introduces the concept of coupled-mode theory in the context of transmission lines. Coupled-mode theory is a large and rich topic that is covered in more detail in other videos. The purpose of this video is just to illustrate what is coupled-mode theory and a few applications. If you are interested in learning more about coupled-mode theory and how it applies to many other things in electromagnetics and photonics, checkout Topic 3 in “21st Century Electromagnetics.”
empossible.net/academics/21cem/
Please visit the course website to see all the course content, download the notes, get links to the latest versions of the notes and videos, and see all the other learning resources.
empossible.net/emp3302/
#electromagnetics #optics #maxwells #electric #magnetic #waves #scattering #microwave #transmission line #resistance #conductance #capacitance #inductance #distributed #circuits #circuittheory #kvl #kcl #rumpf #empossible #microstrip #stripline #coplanar #slotline #coax #coaxial #impedance #characteristicimpedance #telegrapher #Fourier #coupled #mode #theory #directional #coupling 
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Is there any chance on a video/shorts series about electromagnetic absorbers? Specifically the fundamentals on how FSS, circuit analogue absorbers and high-impedance surfaces work?
I do not have all of that, but I do have some . Take a look at Topic 7 here:
empossible.net/academics/21cem/
Ooh, that "hopping power" result is nifty, I should definitely look at the derivation. Would you happen to have intuition for why on a directional coupler the coupled port is on the near side rather than the far side (as seen from the input port)? The story "signal goes in, hops to coupled line, still traveling in same direction, and goes out coupled port" gives the wrong result and I've always wondered why.
I do not think I am following your question exactly. If by "near side" you mean the other port on the same side as your input port, that typically would not show any power. To get power to that port, there would need to be reflection. It is called directional coupling because the wave keeps moving forward. It is just that the power will transfer between the lines periodically. I am not sure if I answered your question or not.
@@empossible1577 I think you described the very thing that my intuition would (also) expect, but this is the opposite of what actually happens. Let's refer to 6:40 and the coupler on the left side of the slide. If I were to attach a signal generator at 1.83GHz, 0dBm to the In port and terminate Out and Rev ports, I would see about -15dBm at the Fwd port. If I then terminated the Fwd port and monitored the Rev port, I would see -35dBm or something due to leakage and imperfections. In other words, the labels on the board match my experience when taking measurements but they are the opposite of what my intuition says should be the case. I am therefore trying to recalibrate my intuition to match experiment.
@@jjoonathan7178 Hmmm...I wonder if the sharp bends are using reflections to behave how you are saying. Looking at the chamfers, I assumed not. I've simulated tons of things like this, but not that specific design so I guess I cannot say for sure.
@@empossible1577 I just uploaded a video on my channel measuring one that was easy to open (not sure if links are allowed). I don't think it's an artifact of bends or chamfers. It seems to be a thing with coupled-line couplers in general, at least microstrip / stripline / suspended line: all my Krytar and Marki and Anritsu and HP couplers work this way. Near port is coupled, far port is isolated, and this happens even if the thru line has no bends or chamfers like on my Krytar couplers. I can't speak for waveguides. But yeah, what happens is the opposite of what my intuition says should happen, and I've long wanted to clear that up.
1 not zero
Are you point out an error? Can you be more specific so I can find it? Sorry!