Patent ID: 8289102
Filing Date: 2012-10-16
Classification: H01P

Abstract:
1. A directional coupler comprising: a main line located on a substrate, said main line having a first end connected to an input port, and a second end connected to an output port; a coupled line located on said substrate and extending along said main line, said coupled line having a first end located at the same side of said directional coupler as said input port and connected to a coupled port, and a second end located at the same side of said directional coupler as said output port and connected to an isolated port, wherein coupling length between said coupled line and said main line is shorter than one-quarter wavelength of power transmitted from said input port to said output port; a first capacitive element located on said substrate and having a first end connected between said coupled port and said first end of said coupled line, and a second end connected to ground; a second capacitive element located on said substrate and having a first end connected between said isolated port and said second end of said coupled line, and a second end connected to ground; and a phase shifter having a first end connected between said isolated port and said first end of said second capacitive element, and a second end connected between said coupled port and said first end of said first capacitive element, wherein said phase shifter