Transmission line and electronic device

A transmission line comprising:

• a laminated body including a plurality of insulator layers laminated together in a vertical direction;
• a first signal conductor layer in the laminated body and extending in a longitudinal direction orthogonal or substantially orthogonal to the vertical direction;
• and
• a first ground conductor layer in the laminated body and being provided above the first signal conductor layer to overlap the first signal conductor layer in the vertical direction;
• wherein
• a first hollow portion is provided in the laminated body so as to be located above the first signal conductor layer and below or adjacent to the first ground conductor layer, the first hollow portion overlaps the first signal conductor layer and the first ground conductor layer in the vertical direction, the plurality of insulator layers include a first insulator layer provided above the first hollow portion, a first upper cavity is provided in the first ground conductor layer, and at least a portion of the first upper cavity overlaps the first hollow portion and the first signal conductor layer in the vertical direction;
• and
• the first ground conductor layer is defined by a conductor material including metal, and the first upper cavity is provided in the conductor material including metal.