Multi-layer substrate suppressing an unwanted transmission mode

A multi-layer substrate comprising a first dielectric layer, a coplanar waveguide line formed on a first surface of said first dielectric layer, and a second dielectric layer formed on said first dielectric layer and having an opening positioned at least on a signal conductor of said coplanar waveguide line,

• wherein said first dielectric layer has a dielectric constant smaller than that of said second dielectric layer.

A multi-layer substrate comprising a first dielectric layer, a coplanar waveguide line formed on a first surface of said first dielectric layer, and a second dielectric layer formed on said first dielectric layer and having an opening positioned at least on a signal conductor of said coplanar waveguide line,

• wherein said first dielectric layer has a dielectric constant smaller than that of said second dielectric layer,
• further including a conductor layer formed on said second dielectric layer,
• further including a feed-through formed to bridge between a pair of second dielectric layer portions, which are positioned on a pair of ground conductors of said coplanar waveguide line, respectively.

A multi-layer substrate comprising a first dielectric layer, a coplanar waveguide line formed on a first surface of said first dielectric layer, and a second dielectric layer formed on said first dielectric layer and having an groove positioned in a region at least in conformity with a signal conductor of said coplanar waveguide line,

• wherein a thickness of said second dielectric layer between a bottom of said groove and said first dielectric layer is smaller than the value of c/{4f·(∈2−1)½}, where c is velocity of light, f is a frequency of a signal propagating in said coplanar waveguide line, and ∈2 is a dielectric constant of said second dielectric layer.

A multi-layer substrate comprising a first dielectric layer, a coplanar waveguide line formed on a first surface of said first dielectric layer, and a second dielectric layer formed on said first dielectric layer and having an groove positioned in a region at least in conformity with a signal conductor of said coplanar waveguide line,

• further including a back ground conductor layer formed on a second surface of said first dielectric layer.

A multi-layer substrate comprising a first dielectric layer, a coplanar waveguide line formed on a first surface of said first dielectric layer, and a second dielectric layer formed on said first dielectric layer and having an groove positioned in a region at least in conformity with a signal conductor of said coplanar waveguide line,

• further including a back ground conductor layer formed on a second surface of said first dielectric layer,
• further including a via contact buried in said first dielectric layer to connect between said back ground conductor layer and ground conductor of said coplanar waveguide line.

A multi-layer substrate comprising a first dielectric layer, a coplanar waveguide line formed on a first surface of said first dielectric layer, and a second dielectric layer formed on said first dielectric layer and having an groove positioned in a region at least in conformity with a signal conductor of said coplanar waveguide line,

• wherein said first dielectric layer has a dielectric constant smaller than that of said second dielectric layer.

A multi-layer substrate comprising a first dielectric layer, a coplanar waveguide line formed on a first surface of said first dielectric layer, and a second dielectric layer formed on said first dielectric layer and having an groove positioned in a region at least in conformity with a signal conductor of said coplanar waveguide line,

• wherein said first dielectric layer has a dielectric constant smaller than that of said second dielectric layer,
• further including a conductor layer formed on said second dielectric layer,
• further including a feed-through formed to bridge between a pair of second dielectric layer portions, which are positioned on a pair of ground conductors of said coplanar waveguide line, respectively.