Patent ID: 7187910

Claim:
A directional coupler comprising: a first transmission device for transmitting a first band signal; a first directional coupling device including a first terminal and a second terminal and spaced apart from said first transmission device by a predetermined distance, said first directional coupling device coupling a part of said first band signal from said first transmission device and generating the coupled signal at said first terminal thereof, said second terminal of said first directional coupling device being connected to a ground terminal; a first inter-digital capacitor having its one side connected to said first transmission device and its other side connected to said first directional coupling device; a second transmission device for transmitting a second band signal; a second directional coupling device including a first terminal and a second terminal and spaced apart from said second transmission device by a predetermined distance, said second directional coupling device coupling a part of said second band signal from said second transmission device and generating the coupled signal at said first terminal thereof, said second terminal of said second directional coupling device being connected to said ground terminal; and a second inter-digital capacitor having its one side connected to said second transmission device and its other side connected to said second directional coupling device.