Transmission line apparatus having conductive strips coupled by at least one additional capacitance element

A transmission line apparatus comprising:

• a substrate with a ground conductor plane;
• and a first signal strip and a second signal strip, which are supported on the substrate and arranged in parallel with each other,
• wherein the apparatus further includes at least one additional capacitance element that connects the first and second signal strips together, and
• wherein the at least one additional capacitance element includes:
• a first additional conductor that is arranged with a space left with respect to the first signal strip;
• a second additional conductor that is arranged with a space left with respect to the second signal strip;
• and
• a third additional conductor that is connected to the first additional conductor at a point and to the second additional conductor at another point, respectively, and
• wherein when measured in a signal transmission direction, a smallest width W3a of the third additional conductor is shorter than a length L1 of the first additional conductor or a length L2 of the second additional conductor, and
• wherein the at least one additional capacitance element has a resonant frequency that is higher than the frequency of a signal being transmitted.