Power Combiner

Do a tree structure of 2-1 splits following 2-1 splits. Four levels will get you 16-1. Wilkinson types are small and wide enough bandwidth at the ISM band you are working with.

Any recommenation on the types of resistors to be use for the wilkinson power combiner since it is using on the ISM band?

Since you are probably ending up with 1 W or less at the other end, the power rating of the resistors should be 1/16 W or so. ordinary surface mount types will do. Double check the data sheets to make sure of the frequency rating. If this network is to be operated at higher power levels, special power resistors, such as made by Anarin http://www.anaren.com/docs/app_notes...0SMD%20RES.pdf should be used.

Thanks for the informations

For power levels of up to a few Watts you can stack up normal 1206 resistors (generally 0,25W each), if cost is an important factor.

If you are looking for a compact low power solution with SMD device have a look at;
http://www.alphaind.com/
some of these will operate at 2.4GHz depending on your requirements.

Newbie,
you have to give requirements about output amplitude and phase, Bandwidth... mechanic performances....so I'll try to help you.

Does anyone have material about squared coaxial lines?
I need design equations about losses reltive to squared or rectangular coaxial lines.. Hope someone can help me.

Thanks in advance
Lupin

hi lupin,
I've seen some material in the antenna handbook (Lo) chapter 28 end of table 4. include impedance, I have not seen anything on losses.

Thanks Dowjones,
anyway, for squared coaxial lines I found equations about characteristic impedance; at the moment for rectangular lines into squared lines I've no formulas.... So, I've thought to use some 3D e.m. software to evaluate the characteristic impedance everytime I change the horizontal (or vertical) dimension of the inner conductor...
Do you think it's a possible method? In this way the results depend on the mesh I'm using and on the accuracy of the code.. So they don't derive from a rigorous analysis like in squared coaxial line.
What do you think?

Regards
Lupin

Hi,
You can make a radial form power combiner very compact.

hello lupin,

well, i've done a similar process with suspended substrate stripline and it works fine. the main problem is that you cannot account the effect of discontinuities

Hello dowjones,
I think it's not the same thing: for a stripline structure for most of e.m.
codes you have formulas to estimate guided lambda, characteristic impedance (given the line width), line width (given the line impedance).
As an example, Ensemble offers this option... Of course you can't consider discontinuity effects but it's a good starting point.

In my case, the rectangular coaxial line is a too particular configuration; in fact I can't find in litterature formulas for the associated line impedance... So I'm obliged to build a configuration by a 3D code, mesh it very carefully, run the simulation and to hope the result to be accurated...
If I consider more lines with different rectangular sections, I can have strong discrepancies between simulated and measured components...

Hope you find some article or formula about configurations of rectangular inner conductors into squared outer conductors.

Regards
Lupin

hi lupin,
I've scanned 4 pages which maybe they are useful for you. I'm afraid the scanned pages give a quite huge archive (which will be uniquely useful for you, and even this it is not sure). do i upload the file (8Mb) or send to you as pm?

regards

As you like Dowjones.. I don't know how many Elektroda people work with rectangular section lines coaxial to squared section lines....
Probably just a few... If you want you can send the material to my e-mail or as a private message...For me it doesn't matter.
What type of formulas did you find? Line Impedance, Losses?

Thanks a lot... you know my interests, you can just ask if you have a question.

Regards
Lupin

they are only 4 scanned pages. the first page is from antenna handbook (by Lo & Lee) the other pages are from Microwave Engineers Handbook (by Hansen and Wheeler 1971 Artech House). I keep the size so that the figures can be read.
regards

I agree with jamez. For a 16 way power divider radial configurations are compct with respect to a corporate structure.

How does it look like? What impedances, lengths?

Just a bit differnt type but you can play with the shape. See the attached file.