You are misunderstanding.Why aren't power waves (as defined by Kurokawa's scattering matrix paper) see more use than travelling waves in research and literature?
For real value reference impedance, there is no difference between Power Wave and Voltage Wave formulations.Perhaps it is because it is much more difficult to measure power waves than travelling waves with a VNA?
What do you search ?Well do a google search for reflection coefficient
and you'll see almost nothing but the travelling wave equation.
Even in IEEE I almost never see s, always gamma.
Assume reactive(lossless) matching network for R+j*X to 50Ohm, it ihas to be conjugate matching, so it is power wave definition, Sqrt(Gamma_P) not Gamma_V.Perhaps by embedding directional couplers at the junction?
Assume reactive(lossless) matching network for R+j*X to 50Ohm, it ihas to be conjugate matching, so it is power wave definition, Sqrt(Gamma_P) not Gamma_V.
I don't disagree, but I find it strange that I've never seen the term "power wave" at any conference I've attended, and have had people ask me what a power wave is when I use the term.Again, Power Wave formulation is most used in RF world.
What community do you attend ?but I find it strange that I've never seen the term "power wave" at any conference I've attended
I've never seen the term "power wave" at any conference I've attended, and have had people ask me what a power wave is when I use the term.
Are you young ?Same here. MTT member from Germany.
Are you young ?
But power waves are proportional to E and B fields, and are linear. Really the only difference is the conjugate terminating impedance.Modern MW engineering uses travelling waves, like S11 = B/A where B is the reflected traveling wave, and A is the incident travelling wave. B and A are moste like E Fields, or "voltages", so to see the power in them you have to square the quantities.
But old school MW engineering, like the type done 40 years ago, involved a lot of directional couplers and thermistor power meters...so Power waves, if you want to call them that, were more en vogue. Of course, even back then there were slotted lines and standing wave meters...measuring voltage standing waves.....
Are they not taught at universities anymore? My university doesn't even have an RF/MW curriculum, but when I look at lecture slides from other universities I never see them mentioned except for maybe a background slide here or there.
No.Modern MW engineering uses travelling waves, like S11 = B/A where B is the reflected traveling wave, and A is the incident travelling wave.
B and A are moste like E Fields, or "voltages", so to see the power in them you have to square the quantities.
If so, what do you call "|a|^2" and "|b|^2" ?but "power waves" is a term I haven't heard about in our RF education.
Right.But power waves are proportional to E and B fields, and are linear.
Really the only difference is the conjugate terminating impedance.
I think so.Are they not taught at universities anymore?
Right.I think it's clear that any instrument that terminates the waves with a real impedance (virtually all of them) cannot distinguish power waves from traveling waves.
From practical point of view, s-parameters with complex value reference impedance are not needed at all.My question is more about why power waves aren't commonly explicitly referred to when analyzing RF systems in literature.
I think it is recent trend, since there is no practical need for generalized s-parameters where port impedances are complex value.My university doesn't even have an RF/MW curriculum,
but when I look at lecture slides from other universities I never see them mentioned except for maybe a background slide here or there.
Well as we said at a VNA's ports, Zi is real so power waves and traveling waves are the same.No.
Commercial RF simulator such as "Keysight ADS" gives S11=0 at conjugate matched condition.
Generalized S-parameters are defined by "Power Wave".
I have actually seen material where traveling waves are referred to as a and b.If so, what do you call "|a|^2" and "|b|^2" ?
Never seen the term "root" power wave, Kurokawa originally called a and b power waves (even though they do not have unit watts).We call "|a|^2" as "incident power wave" and "|b|^2" as "reflected power wave".
Both "a" and "b" are neither voltage nor current.
I call "a" as "root(incident power wave)" and "b" as "root(reflected power wave)", however these names are not general.
Strictly speaking, "a" and "b" are root(power) not power.
However we often call "a" and "b" as power simply.
Commercial RF simulator such as "Keysight ADS" gives S11=0 at conjugate matched condition.
Generalized S-parameters are defined by "Power Wave"..
I agree in the case of s parameters, but it matters with regards to reflection coefficients.From practical point of view, s-parameters with complex value reference impedance are not needed at all.
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