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–3dB Coupler in Waveguide Systems


Figure 1: -3dB-coupler

A -3dB-coupler divides the power arriving on a waveguide up into two equally big portions. At this the phase of the diverted waveguide is shifted by 90°. This phase shift is indicated by blue directional arrows (E field) in the shown figure.

This phase turn is used in many applications (e.g.: Duplexer or Filter) specifically.

To match the lines with the couplers other geometry of the cross-cut a conical deepening is often attached in central place. This is recognizable of the outside also.

The not uses port ist closed by a dummy load.