Equal Split Wilkinson Power Divider - Project Presentation
Bhanwar SinghJ Muralidhara Chary
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.
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.
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.
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
For matching port 2 for even mode excitation,we have to make
We obtain: We can obtain using transmission line equations.
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 :
With the above calculated Z and r values we can find the input impedance at port 1 as
In summary we can establish the following S-parameters for the wilkinson divider:
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