Patent ID: 8432235

Claim:
A coupler comprising: a first conductive pattern provided on a substrate having an insulating property; a second conductive pattern provided on the substrate and placed in opposition to the first conductive pattern; a third conductive pattern provided on the substrate; a fourth conductive pattern provided on the substrate and placed in opposition to the third conductive pattern; a ground potential portion placed around positions on the substrate where the first conductive pattern, the second conductive pattern, the third conductive pattern, and the fourth conductive pattern are placed; a first resistor connecting between the first conductive pattern and the second conductive pattern placed in opposition to each other; and a second resistor connecting between the third conductive pattern and the fourth conductive pattern placed in opposition to each other, wherein: a transmit signal including each of differential signals of mutually opposite phases is supplied to the first conductive pattern and the second conductive pattern and transmitted; and a receive signal including each of differential signals of mutually opposite phases is obtained by the third conductive pattern and the fourth conductive pattern.