The three port network shown above is an Unequal Resistive Power Splitter.
Power arriving at the Input port is delivered, attenuated, to the two output ports.
More power will be delivered to port 1 (dB1), and less power to port 2 (dB2).
The power ratio between port 1 and port 2 can be adjusted to any desired value by selecting the appropriate resistor values.
All ports are matched to Zo.
The table below shows a few examples of the possible combinations.
| dB 1 | dB 2 | Rs (Ohms) | Rt (Ohms) | Ru (Ohms) |
| 0.1 | 44.80 | 0.287 | 4317.704 | 50.582 |
| 1.00 | 24.78 | 2.875 | 406.805 | 56.523 |
| 3.00 | 15.01 | 8.549 | 111.529 | 77.531 |
| 6.02 | 6.02 | 16.666 | 16.666 | OPEN CKT |
The program PUNEQUAL is a calculator, which finds the resistor values needed for an unequal
power splitter of any given output ratio and characteristic impedance.
To run PUNEQUAL, download unequal.zip from the Circuit Design page, and unzip all of the files into a single directory.
Click on PUNEQUAL.EXE to run the program.
Screen shot from PUNEQUAL
Just type in the desired value of Zo, and the desired attenuation at port 1,
then click the "Calculate" button.
Remember that the port 1 attenuation must be LESS than 6.02dB.
The attenuation at port 2, and the resistor values will appear in the boxes below.
The program is written in Borland C++Builder.
The source code is included in the .zip file for those who may want to improve it, or port it.