Stepped Impedance Transformer

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#244 In this video I look at a wider bandwidth implementation of the quarter wavelength impedance transformer - the stepped impedance transmission-line transformer. In essence its a series of multiple quarter wavelength transformers, one is series with the other, which brings a very interesting propriety - the total bandwidth increases.
Impedance matching series:
Resistive matching: • Electronics tutorial -...
Lossless matching part 1: • Lossless Impedance Mat...
Lossless matching part 2: • Lossless Impedance Mat...
Transformer matching part1: • Wideband coupling - Tr...
Transformer matching part2: • Resonant coupling - Tr...
Transformer matching part3: • Coupling experiments -...
Quarter wavelength matching part1: • Quarter wavelength imp...
Quarter wavelength matching part2: • Quarter wavelength imp...
Stub matching: • Stub Impedance Matching
Stepped impedance transformer: • Stepped Impedance Tran...
Used links and further reading:
www.microwaves...
www.microwaves...
eng.libretexts...
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[@Hohey2663]

Hello, and welcome back 😢

[@vincei4252]

Good morning, FesZ. I bought a lifetime supply of these 0:02 variable inductors in the form of very reasonably priced designers kits from Coilcraft here in the states. All available values. The more kits you buy the price of each one goes down. Looking forwards to trying them in some circuits I have waiting.

[@andrewmcfarland57]

Thanks professor Fesz! 🙂

[@bobby9568]

professor? he's a phd student

[@FesZElectronics]

Well, I'm neither a professor nor have a PhD, I just make videos on things I find interesting.

[@bobby9568]

@ that is good enough for us, keep it up! I subbed to your channel when you had less then 1k subs

[@andrewmcfarland57]

@bobby9568 Just thinking ahead.🙂

[@bobby9568]

@ why do you associate professors with being smart? becoming a professor is just having good connections... and be old ....

[@bobby9568]

We want more ltspice simulations

[@MaxPivovarov]

I think the issue with the spike around the center frequency might be caused by the lack of via holes in the separating shielding. This leads to resonance.

[@YouveBeenCabadged]

I can''t see it clearly in the video - but are there any vias on your boards apart from the through holes? It looks like there aren't any vias on the long island of upper ground plane between the S bend traces. Usually RF boards will be stitched with hundreds of vias along both sides of every microstrip trace, so if you've only got the through holes, it might have affected your results.

[@FesZElectronics]

You are right, I didn't notice this before but I don't have enough vias - the ground islands inside the U bends are not connected using vias, there are only vias on the outside of the complete structure. So there is a line of vias all round the complete transmission line, and well in-between the 3 structures there are lines of vias, but I forgot to place vias inside of the structures.

[@Kilohercas]

I would love to see video how you can couple L1 L2 L5 E6 GPS into single feed. it looks like it should be possible only by PCB traces?

[@willthecat3861]

@FesZ Electronics At 1:09... in the video... you have that Zc = sqrt (Z1 * ZL) so that it follows that Zc^2 = Z1 * ZL, and Z1 = Zc^2/ZL. But, right beside that you have that Z1 = sqrt (Zc^2/ZL). What's going on?

[@willthecat3861]

Z1 = Zc * (ZL + j * Zc * tan(B * l)) / (Zc + j * ZL * tan(B * l)) applying the 1/4 wave condition Z1 = Zc * (ZL + j * Zc * ∞) / (Zc + j * ZL * ∞) doin a little sloppy (but ultimately 'valid' algebra, around infinities) Z1 = (Zc^2) / ZL

[@FesZElectronics]

Indeed that is an oversite on my side; the "sqrt" was not supposed to be there...

[@SouravTechLabs]

1:03 - Why the square root on right hand side? Also, 2:19 - Shouldn't it be "40 ohms" instead of "40 MHz"?

[@dr.med.janschiefer7163]

Please stop the horrible automatic audio translations.

[@albertpalau35]

It is the only way I can understand the video, just changing the settings solves it. I don't have it that easy

[@TecraTube]

do you have something more difficult for professionals like me? this seems really easy 😂😂😂