Directional Coupler

What Does Directional Coupler Mean?

A directional coupler is an electronic component having four-port circuits with one port being isolated from the input port and another being considered as a through port. The device is normally used to split the input signal and distributed power. The device couples part of the transmission power by a specific factor through one port. Directional couplers are used in a wide range of applications which involve measurement, power monitoring and other utilities.


Techopedia Explains Directional Coupler

Directional couplers are categorized as passive reciprocal
networks. A directional coupler is used for isolating, eliminating or combining signals in microwave signal routing and radio frequency. The ports in the directional coupler are:

  • Coupled
  • Input
  • Transmitted
  • Isolated

A special design is put into use by which the input power is split between the coupled and output ports in a specific ratio known as the coupling ratio. Depending on the application for which it is used, the key specifications of the directional coupler varies. The parameters/specifications which are mostly varied are the coupling factor, transmission loss, low variation of the coupling attenuation, high directivity and input power. For most directional couplers, the features which are desired are high directivity, good impedance and wide operational bandwidth. But the performance of a directional coupler is computed using the directivity factor. There are different types of directional couplers like single, dual directional, coaxial, waveguide and even combination types.


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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.