[PPRAANet] Technical Question related to UnUn and BalUns

[GEORGE W SHAIFFER]

Still attempting to post.

George W Shaiffer

________________________________
From: GEORGE W SHAIFFER <gshaiffer at msn.com>
Sent: Friday, April 30, 2021 9:51 PM
To: ppraanet-bounces at mailman.qth.net <ppraanet-bounces at mailman.qth.net>
Subject: Technical Question related to UnUn and BalUns

Introduction
Transmission Line Transformers  by Jerry Sevick, W2FMI was originally published by ARRL
>From the back cover: Transmission Line Transformers is packed with practical data on the design and construction
of broadband transformers and baluns.  This book was originally published by ARRL.  Today it remains one of the best
collections on this important subject and was republished in the Noble Classic Series in 1996.

Not an easy read but interesting and has put a question in my mind that searches have not answered.
A little of my background includes Radar maintenance training at FT Sill.  Transmission Lines and Wave guides
were introduced as Science Fiction I with Magnetrons, Klystrons and cavity resonators as SF II.  I have an awareness of
TEM and the Electrical and Magnetic modes in waveguides.  I'm not sure anyone really understands them, so I claim to
be aware.  Enough introduction so back to the text for my problem/question.

>From Chapter 12:
     "As was mentioned in previous chapters, if proper ferrite material is used for the cores of transmission line transformers,
     they can exhibit outstandingly high efficiencies.  This occurs because of the canceling effect of the transmission line currents.
     Energy is transmitted by a transmission line mode instead of by flux linkages as in a conventional transformer.  This holds true
     at the transformer's high -frequency limits,  where standing waves come into play to create a complex transformation ratio* which
     can be different from that of the mid-band ratio."

Finally to my question which was implied in earlier chapters put stated more specifically in Chapter 12 above.

Since these are transformers and intended to match impedances if the energy is not being transferred by flux linkages can anyone
explain how the energy transfer happens?  In most of the text he references TEM mode and I suspect there may be several TEM modes
Is a change in polarization considered a mode change? I think not.
Waveguides utilize TE or TM (Transverse Electric or Transverse Magnetic) while transmission lines can support these modes they are typically
undesirable and most transmission lines will be TEM or quasi-TEM whatever that is. (Transverse Electric Magnetic mode).

If anyone would like to borrow this classic bool let me know or it will end up on my bookshelf.

*complex transformation ratio I assume by complex here he is referencing +jX or -JX reactances that the ratio aquires an inductive or capacitive term and not complicated mathematics.
WHEW!
George
KE0QCC