Re: RF power combiner

From	Joe Gwinn <joegwinn@comcast.net>
Newsgroups	sci.electronics.design
Subject	Re: RF power combiner
Date	2025-10-24 08:51 -0400
Message-ID	<uctmfk169tedb109sqtj1jekmrkekuljl5@4ax.com> (permalink)
References	<10da59f$gcuu$1@dont-email.me> <9e7603ff-39e9-bfc5-612c-c30bb27679eb@electrooptical.net> <10deaqo$26nts$1@dont-email.me>

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On Fri, 24 Oct 2025 00:39:20 +0200, Jeroen Belleman
<jeroen@nospam.please> wrote:

>On 10/23/25 22:48, Phil Hobbs wrote:
>> On 2025-10-22 04:40, Jeroen Belleman wrote:
>>> While musing over a text about transmission line transformers,
>>> combiners, splitters and so on, I came up with a power combiner
>>> that promises a bandwidth spanning from some kHz well into the
>>> GHz domain, with good isolation between input ports, and that
>>> does _not_ have a null where its transmission lines are half a
>>> wavelength long.
>>>
>>> I could find no other examples of this arrangement. The usual
>>> combiners are wire- or coax- wound transformers, with 3 decade
>>> bandwidths in the 100kHz-100MHz ballpark, or Wilkinson things
>>> that only begin to work above half a GHz.
>>>
>>> This design should be able to work from a few kHz up to well
>>> into the GHz domain. Anyway, for what it's worth, here it is.
>>>
>>> Jeroen Belleman
>>>
>>> =========================
>>>
>>> Version 4
>> <snip>
>> 
>> That is one weird-ass combiner, for sure.  Looks like it has to be made 
>> out of coax, on account of the switcheroo in the grounds.
>> 
>> I like it!
>> 
>> Cheers
>> 
>> Phil Hobbs
>> 
>
>The way I drew it was a bit clumsy. It's neater to arrange it
>to have the center conductors cross over instead of the screens.
>It should work quite well though, if constructed correctly. I got
>100kHz-9GHz (-3dB) out of a similar thing, with better than 40dB
>of isolation between the inputs over almost the full bandwidth.
>
>It appears I'm 38 years late though. A guy names Edwards, working for
>Rockwell, came up with exactly the same thing in 1988! US patent 4774481.
>
>Oh well.
>
>Jeroen Belleman

A useful comparison is "Coaxial AC Bridges" by Kibble and Rayner,
1984, 107 pages.  

Joe

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Thread

RF power combiner Jeroen Belleman <jeroen@nospam.please> - 2025-10-22 10:40 +0200
  Re: RF power combiner Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2025-10-23 16:48 -0400
    Re: RF power combiner Jeroen Belleman <jeroen@nospam.please> - 2025-10-24 00:39 +0200
      Re: RF power combiner Joe Gwinn <joegwinn@comcast.net> - 2025-10-24 08:51 -0400
        Re: RF power combiner Jeroen Belleman <jeroen@nospam.please> - 2025-10-24 19:21 +0200
        Re: RF power combiner Bill Sloman <bill.sloman@ieee.org> - 2025-10-25 04:22 +1100
      Re: RF power combiner Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2025-10-24 13:17 +0000
        Re: RF power combiner Jeroen Belleman <jeroen@nospam.please> - 2025-10-24 19:15 +0200
          Re: RF power combiner Bill Sloman <bill.sloman@ieee.org> - 2025-10-25 14:49 +1100
        Re: RF power combiner Joe Gwinn <joegwinn@comcast.net> - 2025-10-24 15:33 -0400
        Re: RF power combiner john larkin <jl@glen--canyon.com> - 2025-10-24 12:48 -0700
    Re: RF power combiner Bill Sloman <bill.sloman@ieee.org> - 2025-10-24 18:17 +1100

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