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Tunable power divider

Started by cogwsn 3 years ago7 replieslatest reply 3 years ago121 views

Hi, 

Can anyone please suggest any tunable power divider available in market. I tried searching a lot, but found only research articles or patents. For a project related to simultaneous information and power transfer, I am looking for 2 way tunable power divider. By tunable, I mean the ratio of divided powers can be varied. 

Regards

Sumit 

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Reply by neiroberMarch 3, 2020

Hi Sumit,

What is the frequency range required?  Must this be a passive device, or can it be powered?

-- Neil


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Reply by cogwsnMarch 3, 2020

Hi Neil, 

Thanks much for reply. I tried much to search. 

Upto 6 GHz should be OK for me. I would like to check both options, passive as well as active. If you can share the link, that will be great.  

Regards

Sumit  


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Reply by neiroberMarch 3, 2020

Sumit,

Sorry, but I don't have anything specific.  Since passive devices tend to be based on transformers, they tend to have a fixed loss.  Maybe you could just use a conventional two-way splitter, and place a variable attenuator in one leg.  Then one output leg would be -3 dB (plus some implementation loss), and the other leg would be lower than -3 dB (e.g. -4 dB to -10 dB). 

If you want the total power to add to a constant amount, you could obtain that by properly adjusting variable attenuators placed on each leg.

-- Neil

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Reply by cogwsnMarch 3, 2020

Ok, thanks, this one I understood. And what should be the implementation for an active divider. So that I make sure power_out_1 + power_out_2 = power_in; I mean if this is possible. 

Regards

Sumit 

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Reply by neiroberMarch 3, 2020

So, if P1 + P2 = Ptotal,

P2/Ptotal = 1 - P1/Ptotal

let P1 dB = 10log10(P1/Ptotal)

    P2 dB = 10log10(P2/Ptotal)

then

P2 dB = 10log10(1 - 10^(P1dB/10))


e.g.  for P1 dB =-3.01 dB,

P2 dB = 10log10((1 - 10^(-3.01/10)) = -3.01 dB

Note P1 dB and P2 dB are always negative numbers.


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Reply by jimelectrApril 21, 2020

Interesting problem/challenge!  I'm surprised to see this on DSP Related, though.  I suppose one could build an electromechanical device whereby one could steer the input power to either of the output ports while losing as little power as possible to heat.  Neil's suggestion with attenuators would be lossy, of course.  I imagine something like a copper trace on suitable dielectric board connecting to the input, two parallel copper traces on another piece of dielectric spaced far enough apart as to minimally couple, and a mechanism for the input board to slide over the output board.  At one extreme, the input line would run parallel directly over one of the output lines, and at the other extreme, it would run parallel directly over the other output line.  Any retirees looking for an RF project?  One of the big challenges would be keeping isolation between the output ports while keeping insertion loss between the input and output ports low.

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Reply by jfrsystemsMarch 3, 2020

I may have completely misunderstood your question.

I assume you are talking about an analogue signal in a transmission line context, say 50 ohms. If so, you could use a 2:1 power splitter and a switched attenuator, so that one o/p of the splitter is a reference and the other is attenuated relative to it. Power splitters can be found from many vendors, but MiniCircuits is a good starting point. A switched attenuator may have 1dB steps. Again MiniCircuits have parallel and serial control with variation from 0 - 31dB and this is typical.

If this is a bench hook-up instead of a circuit board arrangement look to vendors like Fairview Microwave for both components but expect to pay a few thousand dollars.

Rgds. JFR.