Abstract: A high-frequency package includes a first dielectric substrate having a signal line and a grounding conductor provided on a back side, a high-frequency element connected to a back side of the first dielectric substrate with a first connection conductor therebetween, a second dielectric substrate having a signal line and a grounding conductor provided on a front side facing the back side with the high-frequency element therebetween, and second connection conductors that are arranged so as to surround the high-frequency element and connect the grounding conductor on the back side of the first dielectric substrate and the grounding conductor on the front side of the second dielectric substrate. In the high-frequency package, a dielectric space surrounded by a conductor pattern is formed in the front side of the second dielectric substrate under the high-frequency element.

Abstract: In a multilayer substrate, a quasi-coaxial line is formed as a structure for transmitting a high-frequency signal generated by a mounted high-frequency device from an uppermost layer to a lowermost layer to externally output and for transmitting an externally input high-frequency signal from the lowermost layer to the high-frequency device. The quasi-coaxial line has: a central conductor being a vertical through hole via that connects between a metal pattern formed on an upper surface of the uppermost layer and a metal pattern formed on a lower surface of the lowermost layer; and outer conductors being a plurality of interlayer vias that are circularly arranged around the central conductor and connect between two or more layers. Whole or a part of the vertical through hole via is substituted by a capacitor structure formed of conductor pads facing each other without any via.

Abstract: A high-frequency package includes a first dielectric substrate having a signal line and a grounding conductor provided on a back side, a high-frequency element connected to a back side of the first dielectric substrate with a first connection conductor therebetween, a second dielectric substrate having a signal line and a grounding conductor provided on a front side facing the back side with the high-frequency element therebetween, and second connection conductors that are arranged so as to surround the high-frequency element and connect the grounding conductor on the back side of the first dielectric substrate and the grounding conductor on the front side of the second dielectric substrate. In the high-frequency package, a dielectric space surrounded by a conductor pattern is formed in the front side of the second dielectric substrate under the high-frequency element.

Abstract: In a multilayer substrate, a quasi-coaxial line is formed as a structure for transmitting a high-frequency signal generated by a mounted high-frequency device from an uppermost layer to a lowermost layer to externally output and for transmitting an externally input high-frequency signal from the lowermost layer to the high-frequency device. The quasi-coaxial line has: a central conductor being a vertical through hole via that connects between a metal pattern formed on an upper surface of the uppermost layer and a metal pattern formed on a lower surface of the lowermost layer; and outer conductors being a plurality of interlayer vias that are circularly arranged around the central conductor and connect between two or more layers. Whole or a part of the vertical through hole via is substituted by a capacitor structure formed of conductor pads facing each other without any via.

Abstract: A thermal recording sheet having on a support a thermal recording layer adapted for developing color when heated has an outermost surface layer formed by bringing it into contact with the surface of a smooth body when it is in a wet state, drying it and separating it from the surface of the smooth body. The sheet has a surface which is so smooth that when a first straight line extending in parallel to the centerline of a roughness curve as obtained in accordance with the method of JIS B0601 crosses the roughness curve with a contact ratio of 10%, a second straight line extending in parallel to the centerline and between it and the first straight line and having a distance of 1.5 .mu.m from the first straight line crosses the roughness curve with a contact ratio of at least 80%. The sheet is, therefore, easy to bring into intimate contact with a thermal head and is of high image quality and sensitivity.

Abstract: A thermal recording sheet having on a support a thermal recording layer adapted for developing color when heated has an outermost surface layer formed by bringing it into contact with the surface of a smooth body when it is in a wet state, drying it and separating it from the surface of the smooth body. The sheet has a surface which is so smooth that when a first straight line extending in parallel to the centerline of a roughness curve as obtained in accordance with the method of JIS B0601 crosses the roughness curve with a contact ratio of 10%, a second straight line extending in parallel to the centerline and between it and the first straight line and having a distance of 1.5 .mu.m from the first straight line crosses the roughness curve with a contact ratio of at least 80%. The sheet is, therefore, easy to bring into intimate contact with a thermal head and is of high image quality and sensitivity.