This document discusses power dividers and describes the design of an equal-split Wilkinson power divider. It explains that a power divider splits an input power signal into two or more output signals of lower power. A Wilkinson power divider uses quarter wave transformers to split power in a 3dB ratio. The document then provides specifications for designing a Wilkinson power divider to operate at 2.4GHz using a substrate with permittivity of 3.38 and thickness of 1.524mm. It calculates the impedance values needed for the divider and uses a circuit design tool to calculate the microstrip line lengths and widths.

1. Bhanwar Singh
J Muralidhara Chary

2.  Power divider divides input power into two
or more signals of lesser power.
 Passive circuits
 E.g. T junction power divider, resistive
divider, Wilkinson divider.

3.  Providing a signal sample for
measurement or monitoring.
 In feedback circuits.
 In combining feeds to and from antennae
 Providing taps for cable distributed
systems such as cable TV.
 Separating transmitted and received
signals on telephone lines.

4.  Can be used to split power in any ratio.
 Lossless when the output ports are
matched i.e. only reflected power gets
dissipated.
 3-dB power divider makes use of quarter
wave transformers.
 Easily fabricated, cheap and high
performing.

5.  Design of Equal -Split Wilkinson power
divider with specifications :
 f = 2.4 GHz.
 Source Impedance = 50 ohms.
 Load Impedance = 50 ohms
 Substrate permittivity = 3.38
 Thickness of substrate = 1.524 mm
 Thickness of conductor = 0.15 mm

8. For matching port 2 for even mode excitation,we have to make

9.  We obtain:
 We can obtain using transmission line
equations.

10. Looking into port 2 we see a impedance of r/2.
For port 2 to be matched for odd mode excitation we select r=2.
Thus we obtain :

11.  With
the above calculated Z and r values
we can find the input impedance at port 1
as

12.  In
summary we can establish the following
S-parameters for the wilkinson divider:

13. Z0 √2 Z0 (Charteristic 2Z0 (Shunt Resistor)
Impedance of quarter
wave transformer)
50 Ω 70.71 Ω 100 Ω
Then we used LINECALC to calculate length and width of microstrip lines –
For Zo=50 Ohm, at λ/4 W=3.37 mm, L= 19.19mm
For Z= √2Zo=70.71 Ohm at λ/4 W= 1.56mm, L=19.86 mm

16. m1
freq= 2.466GHz
dB(S(2,1))=-3.042
0
m1
-5
dB(S(3,1))
dB(S(2,1))
dB(S(1,1))
-10
-15
-20
-25
1.0 1.5 2.0 2.5 3.0 3.5 4.0
freq, GHz

17. Thank you for your kind attention !!