Abstract: A transmission line includes first, second, third, and fourth signal lines, and first, second, third, and fourth electrode pads respectively connected thereto. A first main surface of an external connection portion includes a first region in which the first electrode pad and the second electrode pad are provided, and a second region in which the third electrode pad and the fourth electrode pad are provided. Each of the first electrode pad and the second electrode pad, in a plan view, is surrounded by a ground electrode, and at least one of the third electrode pad and the fourth electrode pad, in the plan view, includes a portion that is not surrounded by the ground electrode.

Abstract: A multilayer body has a structure including insulating layers stacked on each other in an up-down direction. A first conductive layer is on a top main surface of one of the insulating layers. A first signal is transmitted through the first conductive layer. A second conductive layer is on a same insulating layer that the first conductive layer is on. The second conductive layer is on a same main surface as the top main surface or the bottom main surface of the insulating layer on which the first conductive layer is located. A second signal having a higher frequency than the first signal is transmitted through the second conductive layer. A top conductive layer is above the second conductive layer. A thickness of the second conductive layer in the up-down direction is smaller than that of the first conductive layer in the up-down direction.

Abstract: A conductor non-formed portion where no conductor layer exists is provided in a first ground conductor layer. A multilayer body is provided with a void where no insulating resin exists. At least a portion of the conductor non-formed portion is provided in a first area positioned at a right of a first interlayer connection conductor with respect to a multilayer body left-right direction and at left of a second interlayer connection conductor with respect to the multilayer body left-right direction in a view in a multilayer body downward direction. At least a portion of a void overlaps with the conductor non-formed portion in the view in the multilayer body downward direction and is provided above a first signal conductor layer with respect to a multilayer body up-down direction and below the first ground conductor layer with respect to the multilayer body up-down direction.

Abstract: A transmission line includes first, second, third, and fourth signal lines, and first, second, third, and fourth electrode pads respectively connected thereto. A first main surface of an external connection portion includes a first region in which the first electrode pad and the second electrode pad are provided, and a second region in which the third electrode pad and the fourth electrode pad are provided. Each of the first electrode pad and the second electrode pad, in a plan view, is surrounded by a ground electrode, and at least one of the third electrode pad and the fourth electrode pad, in the plan view, includes a portion that is not surrounded by the ground electrode.