A resin sheet is provided having low dielectric properties, and a circuit board material using such a sheet. The resin sheet includes a resin layer containing a cyclic polyolefin resin copolymer having a crystal melting peak temperature of less than 100° C., the resin sheet having a dielectric loss tangent at 12 GHz of less than 0.005.

A fiber-composite part having one or more electronic components that are located in arbitrary regions of the internal volume of the part are fabricated using a preform charge. The preform charge has a structure that corresponds to that of the mold cavity in which the part is being formed. By incorporating the electronic components in the preform charge, such components are then precisely located, spatially oriented, and constrained, and such location and orientation is maintained during molding to produce a part with the electronic components in the desired locations and orientations within its internal volume.

A circuit board according to an embodiments includes an insulating portion comprising a plurality of insulating layers, wherein the insulating portion includes: a first insulating portion; a second insulating portion disposed on the first insulating portion and having a coefficient of thermal expansion corresponding to the first insulating portion; and a third insulating portion disposed under the first insulating portion and having a coefficient of thermal expansion corresponding to the first insulating portion; wherein the first insulating portion includes a prepreg including glass fibers, and wherein the second and third insulating portions include a resin coated copper (RCC) with a coefficient of thermal expansion in the range of 10 to 65 (10.sup.−6 m/m.Math.k).

A circuit board according to an embodiment includes an insulating layer; and a via portion disposed in a via hole formed in the insulating layer; wherein the via portion includes: a first pad disposed on a lower surface of the insulating layer; a second pad disposed on an upper surface of the insulating layer; a third pad disposed in the via hole and disposed on the first pad; and a connection portion disposed in the via hole and disposed between the second pad and the third pad.

A printed circuit board package structure includes a substrate, plural ring-shaped magnetic elements, a support layer, and first conductive layers. The substrate has two opposite first and second surfaces, first ring-shaped recesses, and first grooves. Each of the first ring-shaped recesses is communicated with another first ring-shaped recess through at least one of the first grooves, and at least two of the first ring-shaped recesses are communicated with a side surface of the substrate through the first grooves to form at least two openings. The ring-shaped magnetic elements are respectively located in the first ring-shaped recesses. The support layer is located on the first surface, and covers the first ring-shaped recesses and the first grooves. The support layer and the substrate have through holes. The first conductive layers are respectively located on surfaces of support layer and substrate facing the through holes.

A fluororesin composition is provided. The fluororesin composition comprises the following constituents: (A) a first fluororesin, which is polytetrafluoroethylene (PTFE) resin; (B) a first filler, which is a flat glass fiber; and (C) particles of a second fluororesin, which are coated with polysiloxane,
wherein, the particle size of the polysiloxane-coated particles of second fluororesin ranges from 0.2 μm to 80 μm, and the melting point of the second fluororesin is lower than the melting point of the first fluororesin.

A fluoride-based resin prepreg and a circuit substrate using the same are provided. The fluoride-based resin prepreg includes 100 PHR of a fluoride-based resin and 20 to 110 PHR of an inorganic filler. Based on a total weight of the fluoride-based resin, the fluoride-based resin includes 10 to 80 wt % of polytetrafluoroethylene (PTFE), 10 to 50 wt % of fluorinated ethylene propylene (FEP), and 0.1 to 40 wt % of perfluoroalkoxy alkane (PFA). The circuit substrate includes a fluoride-based resin substrate and a circuit layer that is formed on the fluoride-based resin substrate.

A fiber-composite part having one or more electronic components that are located in arbitrary regions of the internal volume of the part are fabricated using a preform charge. The preform charge has a structure that corresponds to that of the mold cavity in which the part is being formed. By incorporating the electronic components in the preform charge, such components are then precisely located, spatially oriented, and constrained, and such location and orientation is maintained during molding to produce a part with the electronic components in the desired locations and orientations within its internal volume.

New glass compositions and applications thereof are disclosed. A glass composition as described herein can include 50 to 55 weight percent SiO.sub.2, 17 to 26 weight percent B.sub.2O.sub.3, 13 to 19 weight percent Al.sub.2O.sub.3, 0 to 8.5 weight percent MgO, 0 to 7.5 weight percent ZnO, 0 to 6 weight percent CaO, 0 to 1.5 weight percent Li.sub.2O, 0 to 1.5 weight percent F.sub.2, 0 to 1 weight percent Na.sub.2O, 0 to 1 weight percent Fe.sub.2O.sub.3, 0 to 1 weight percent TiO.sub.2, and 0 to 8 weight percent of other constituents. Also described herein are glass fibers formed from such compositions, composites, and articles of manufacture comprising the glass compositions and/or glass fibers.

A metamaterial electromagnetic absorber includes a substrate having a first surface on which electromagnetic waves are incident and a second surface opposite the first surface. The substrate is made of a metamaterial. The metamaterial electromagnetic absorber also includes a first inductive conduction pattern and a second inductive conduction pattern formed on the first surface and the second surface, respectively.