Design of a Resistive Attenuator

In RF/Microwave applications, there are times an attenuator is needed to reduce the magnitude of the signal while maintaining the impedance matching at both the input and the output ports. A simple attenuator can be realized with three resistors with two of them equal in values. This applet implements the design equations for such resistive network.

Brief User's Guide

First, the user needs to specify the characteristic impedance Z0. Then, there are three parameters to joggle: {R1, R2, alpha} with alpha being the attenuation in dB. When one of the parameters is fixed, the other two can be solved for.

• A click on the "Solve for R2, alpha" causes the program to find R2, alpha with the given R1 value
• A click on the "Solve for R1, alpha" causes the program to find R1, alpha with the given R2 value
• A click on the "Solve for R1, R2" causes the program to find R1, R2 with the given alpha value

Reference

[1] David M. Pozar, "Microwave Engineering", p.222, Addison-Wesley, New York, 1990.