A ceramic substrate and a method for production thereof are provided, in which the ceramic substrate includes a composite of : a first ceramic layer including Sr anorthite and Al.sub.2O.sub.3 or an oxide dielectric with a dielectric constant higher than that of Al.sub.2O.sub.3; and a second ceramic layer including Sr anorthite and cordierite and having a dielectric constant lower than that of the first ceramic layer.

Pastes are disclosed that are configured to coat a passage of a substrate. When the paste is sintered, the paste becomes electrically conductive so as to transmit electrical signals from a first end of the passage to a second end of the passage that is opposite the first end of the passage. The metallized paste contains a lead-free glass frit, and has a coefficient of thermal expansion sufficiently matched to the substrate so as to avoid cracking of the sintered paste, the substrate, or both, during sintering.

A module 1a includes an electronic component 3a, and also includes a wiring substrate 2 on one principal surface of which the electronic component 3a is mounted and in which a radiator 4 for dissipating heat generated from the electronic component 3 is provided. The radiator 4 includes a heat dissipation section 4a that is provided so that a part thereof is exposed to a side surface of the wiring substrate 2. In this case, because the heat dissipation section 4a is provided so that a part thereof is exposed to the side surface of the wiring substrate 2, the heat from the electronic component 3a can be dissipated through the side surface of the wiring substrate 2.

A radio frequency module includes: a module board including a first principal surface and a second principal surface on opposite sides of the module board; an antenna connection terminal; a filter that is on the first principal surface and connected to the antenna connection terminal, wherein the filter includes one or more inductors and one or more capacitors, and is configured to allow a transmission signal and a reception signal to pass through; and a reception low noise amplifier on the second principal surface and configured to amplify the reception signal.

A wiring board includes: a base material including, on one side of the base material, a protruding part that protrudes toward an outside, wherein the protruding part has a shape in which a center portion of a principal surface rises from the outer periphery, and a plurality of external connection terminals is arranged on the principal surface. A composite substrate includes: the above-mentioned wiring board and a metallic frame member, wherein the frame member includes an opening whose shape is corresponding to a shape in a plan view of the protruding part, and the frame member is arranged such that the opening surrounds the protruding part to fill a periphery of the protruding part. An electric device includes: an electric element on a right face of the wiring board.

A module is provided that includes a wiring substrate having a major surface, a plurality of components mounted on the major surface, and a conductor incorporated resin body mounted on the major surface. Moreover, the conductor incorporated resin body is disposed between the plurality of components and includes a conductor pattern therein that is grounded.

A multilayer substrate that includes a first ceramic layer that is a dense body, a second ceramic layer that has open pores, and a resin layer adjacent the second ceramic layer, wherein a material of the resin layer is present in the open pores of the second ceramic layer.

A ceramic wiring board that includes a ceramic insulator and a via-conductor. The ceramic insulator includes a crystalline constituent and an amorphous constituent. The via-conductor includes a metal and an oxide. The crystalline constituent and the oxide include at least one metal element in common. A tubular region having a thickness of 5 μm adjoins and surrounds the via-conductor and has a higher concentration of the metal element than the ceramic insulator.

A sintered compact includes an alumina phase as a primary phase, and further includes an amorphous phase containing Si and Mn and a cordierite phase. The sintered compact has a porosity of higher than or equal to 1.1% and less than or equal to 5.0%. Preferably, I1/(I1+I2) is greater than or equal to 0.20 and less than or equal to 0.45, where I1 is the strength of the main peak of cordierite obtained by an XRD method, and I2 is the strength of the main peak of alumina.

An electronic element mounting substrate according to an aspect of the present disclosure is provided with a substrate and a plurality of electrodes. The substrate includes an electronic element mounting region. The plurality of electrodes are located around the electronic element mounting region. The substrate includes the electronic element mounting region and at least one of a first protrusion portion spanning between the plurality of electrodes or a second protrusion portion spanning between the plurality of electrodes from an outer edge of the substrate in a plan view.