# The Waveguide Explanation You Wish You’d Had At School

Anyone who has done an electronic engineering qualification will at some point have had to get to grips with transmission lines, and then if they are really lucky, waveguides. Perhaps there should be one of those immutable Laws stating that for each step in learning about these essential parts, the level of the maths you are expected to learn goes up in an exponential curve, for it’s certainly true that most of us breathe a hefty sigh of relief when that particular course ends. It’s not impossible to understand waveguides though, and [Old Hack EE] is here to slice through the formulae with some straightforward explanations.

First of all we learn about the basics of propagation in a waveguide, then we look at the effects of dimension on frequency. Again, there’s little in the way of head-hurting maths, just real-world explanations of cutt-off frequencies, and of coupling techniques. For the first time we’ve seen, here are simple and understandable explanations of the different types of splitter, followed up by the famous Magic T. It’s all in the phase, this is exactly the stuff we wish we’d had at university.

The world needs more of this type of explanation, after all it’s rare to watch a YouTube video and gain an understanding of something once badly taught. Take a look, the video is below the break.

## 13 thoughts on “The Waveguide Explanation You Wish You’d Had At School”

1. Aaron says:

Waveguides and RF in general are really the dark arts they work with black magic and witchcraft

2. The Commenter Formerly Known As Ren says:

Well, that was more than I remembered from RF Communications class!

3. AZdave says:

Except that I DID get that instruction in my underclass Electromagnetic Waves class at university some 56 years ago. Hardly the “first time” waveguides have been properly explained.

1. Nkosi says:

Indeed, that would be an undergraduate Physics course, I presume, some 56 years ago which shows just how long this topic has been known about and that is just the tip of the iceberg as it goes back way longer than would be suggested here.

1. HaHa says:

Typically for EEs.
You get EM fields in the Physics survey.
Trig substitution in calc, so you can work fields problems.

Part of the Calc/Physics ‘weed out’ sequence that all Engineers and real scientists take.
Not ‘scientists’ though…Apparently they take ‘Apostrophies-theory, practice and final solution’.

Until you pass the first physics and calc, you’re advisor wont know your name.
First semester freshman year if ur prepared.
Done in AP classes for the good students.
Failed twice on the way to new major for most.

These classes are the reason many Engineering schools freshman class is bigger then the rest of the school (Including undergrad, grad, faculty, admin, support staff, hookers and blow suppliers.)

Then you get it again. Jr/Sr level fields/antenna design class.
One of the last though classes, along with controls and solid state.
It was all work.
We used to plot the profs death in detail (Orient express style, we were ALL going to do it), just as a release.

You pass that and your not leaving with a business or CompSci degree.

Arm wavy explanations are fine.
Until someone hears them and thinks they understand.
Don’t kid yourself.

Dont call yourself a ‘man of science’ because you take experimental vaccines for diseases you’ve had 5 times, wear dust masks driving in car alone.
Do the work.
I digress.

2. PurposelyCryptic says:

A lot of schools have just stopped functional explanations in favor of just dumping equations on their students, and the absence of easy associations to their existing knowledgebase has really hampered effective comprehension.

You have to remember, in general, humanity as a whole has a remarkably short memory when it comes to practices, norms and standards – generally at most two generations, or 40-50 years. Anything before that is treated as never having happened, or treated as “historical” and mentally dissociated from applying or being relevant to current life.

It doesn’t matter if something was an everyday norm 50 years ago, or 500, it all gets mentally categorized in the same way unless active, directed attention and thought is applied to it, which, for the general population, on any one subject, occurs rarely enough to be statistically insignificant.

Basically, humanity is weird, and our cultural memory is terrible outside a very short time frame, likely due to a lack of evolutionary advantage resulting from it.

1. HaHa says:

Engineering school is fundamentally practical.
Let relativism into engineering and the bridges will all fall down.

Civil engineering still uses knowledge gained thousands of years ago (soil mechanics is largely experience based).
As you note: Darwin is waiting for us to forget.

Engineering predates ‘science’ as currently practiced.
‘Applied science’ is a halfwits definition of engineering.

4. shinsukke says:

Unsure if this video is about hi-tech RF magic, or plumbing apparatus

1. Piotrsko says:

Both but only if you understand the theory

5. Jim D says:

I do agree that straight forward explanations are in short supply in many engineering disciplines. Case in point, I was working on a WiFi prototype and I wanted to understand some of the DSP operations better. I went to this young smart engineer and he said, “Easy.” and shows me a list of complicated linear algebra equation as if this was obvious. Next I went to an older engineer and he explained in 10 minutes using just words how it worked and basically explained everything I never understood from my DSP classes in school as well. Yes there is a need for lucid clear explanations. Many people got a set of lectures many years ago which were given by a professor who may not have understood it that well themself.

6. dianea says:

Everything is a waveguide. We are living within waveguides right now.

1. HaHa says:

For example: Butt cheeks.

7. Nkosi says:

Waveguides are a standard part of an undergraduate level Physics course and certainly not a school level topic which would explain why many people are not aware of their existence. DSP is also not a school level topic. The Mathematics level for Waveguides is too advanced for school that is why the topic is introduced to those students that is is relevant to at undergraduate level of which Electrical and Electronics Engineering is a good example.

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