Directional Coupler Calculator

This page provides a directional coupler calculator. Use it to determine key parameters like coupling, coupling loss, insertion loss, and directivity.

Directional Coupler Equation

The directional coupler is a crucial component in RF conformance tests for many wireless devices. It’s also used to tap off power to other RF circuits from the main transmission path. Directional couplers are primarily characterized by two factors: the coupling factor and the directivity.

EXAMPLE:

INPUTS:

• P1 = 30dBm
• P2 = 29.5dBm
• P3 = 1dBm
• P4 = 5dBm

OUTPUTS:

• Coupling (dB) = 7.78
• Coupling Loss (dB) = 0.8
• Insertion Loss (dB) = -0.73
• Directivity (dB) = 7

A directional coupler has four ports:

• Input Port
• Output Port (Through Port)
• Coupled Port
• Isolated Port

The following formulas are used in the directional coupler calculator. Directivity measures the ratio of power at the coupled port to the isolated port.