Patent ID: 7414201

Claim:
A transmission line pair comprising: a first transmission line; and a second transmission line which is so placed in adjacency to the first transmission line that a coupled line region is formed, the coupled line region having a coupled line length being 0.5 or more time an effective wavelength in the first transmission line at a frequency of a transmitted signal, wherein in the coupled line region, the first transmission line comprises a first signal conductor which is placed on one surface which is either a top face of a substrate formed from a dielectric or semiconductor or an inner-layer surface parallel to the top face and which has a linear shape along a transmission direction thereof, and the second transmission line comprises a second signal conductor which is placed on the one surface of the substrate and which partly includes a transmission-direction reversal region for transmitting a signal along a direction having an angle of more than 90 degrees with respect to the transmission direction within the plane of the placement, and which has a line length different from that of the first signal conductor, wherein an absolute value of a difference between a product of the coupled line length and a square root of an effective dielectric constant of the first transmission line and a product of the coupled line length and a square root of an effective dielectric constant of the second transmission line is 0.5 or more time a wavelength at the frequency of the signal transmitted in the first transmission line or the second transmission line.