Re: RF power combiner

From	Jeroen Belleman <jeroen@nospam.please>
Newsgroups	sci.electronics.design
Subject	Re: RF power combiner
Date	2025-10-24 19:21 +0200
Organization	A noiseless patient Spider
Message-ID	<10dgci1$2o0di$2@dont-email.me> (permalink)
References	<10da59f$gcuu$1@dont-email.me> <9e7603ff-39e9-bfc5-612c-c30bb27679eb@electrooptical.net> <10deaqo$26nts$1@dont-email.me> <uctmfk169tedb109sqtj1jekmrkekuljl5@4ax.com>

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On 10/24/25 14:51, Joe Gwinn wrote:
> 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

I read that, but it's a long time ago. Maybe I should read
it again.

Jeroen Belleman

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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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