Compact Directional Coupler with Different Input/Output Wave Resistances Line of Transmission Lines

The classical design of the directional coupler has four input/output transmission lines with wave resistances of 50 ohms, which does not allow them to be connected to devices with excellent resistance, for example, 75 ohms without matching devices. In this paper, a technique is proposed for obtaining a directional coupler with different wave resistances of input/output lines, which allows using such devices without additional matching devices if they are connected to lines with different resistances.