Unequalsplit
Wilkinsons
Revised August
13, 2011
Click
here to go to our general discussion of Wilkinson power splitters
Click
here to go to our unequalsplit power divider calculator, it
handles Wilkinsons, ratraces and branchline couplers!
Our material on unequalsplit
Wilkinsons is spread onto the following pages:
Split
Tee Power Divider
 the original unequal Wilkinson splitter from 1965
Unequal
split Wilkinsons, the rest of the story (Microwaves101 exclusive,
from 2009!)
Maximallyflat
transformers used in unequal split Wilkinsons
Kouzoujian's
Nway splitter  uses unequal splitters in a planar layout
(Microwaves101 exclusive!)
Traveling
wave combiner (mostly used to create equal outputs but unequal
math is required)
Nway,
unequal split Wilkinsons  by Paul Hubbard and Greg Ordy of
Seed Solutions (Microwaves101 exclusive!)
Our page on the
rest of the story on unequalsplit Wilkinsons derives the math
behind the impedance calculations. We'll show you an extra degree
of freedom that the classic unequalsplit Wilkinson equations don't
provide.
We are talking about twoway
Wilkinson splitters here, but of course you can make unequal split
Nway dividers. The way to make
power split unequally requires two things: the quarterwave sections
must be of different impedance, to encourage more of the signal
to travel in/out the lowerimpedance arm, and a second set of quarterwave
sections are needed, to transform the arm impedances back to 50
ohms. The structure looks similar to a twostage Wilkinson without
the second isolation resistor (here "R_{W}" is
the Wilkinson isolation resistor).
Topology
for unequalsplit Wilkinson

The above image and many more
are available in a Word document you can get in our download
area (for free).
What constitutes a valid solution
to the unequal splitter network? There are really just three criteria
that must be met:
 All ports are perfectly matched
at center frequency
 Infinite isolation is achieve
at center frequency
 In the even mode (exciting
Port 1) the splitter is lossless.
When you look at any of the
unequalWilkinson solutions, keep an eye on these three properties!
