High-frequency signal transmission line and electronic apparatus

An electronic apparatus comprising a high-frequency signal transmission line and a metal article that are disposed in a casing, the high-frequency signal transmission line comprising:

• a laminate that is obtained by laminating insulating layers and has a first main surface and a second main surface;
• a linear signal line disposed in the laminate;
• a first ground conductor that is disposed in the laminate, faces the signal line via one of the insulating layers, and continuously extends along the signal line, wherein in a portion of the first ground conductor facing the signal line substantially, no opening is disposed and wherein the first ground conductor is located near the first main surface with respect to the signal line;
• and
• a second ground conductor that is disposed in the laminate, faces the first ground conductor via the signal line sandwiched therebetween, and has a plurality of openings arranged along the signal line, wherein the second ground conductor is located near the second main surface with respect to the signal line;
• wherein the linear signal line, the first ground conductor and the second ground conductor define a stripline having a triplate structure;
• wherein a main surface of the high-frequency signal transmission line near the first ground conductor with respect to the signal line is in contact with the metal article;
• and
• wherein a main surface of the high-frequency signal transmission line near the second ground conductor with respect to the signal line is opposed to the casing at a specified distance.