Provided are a printed circuit board configured to achieve reduction in impedance of a differential transmission line extending in a stacking direction, and an optical module. The printed circuit board includes a stacking-direction differential transmission line extending in the stacking direction, including: a differential signal via pair including a first signal via and a second signal via; and a plurality of conductor plate pairs each including a first conductor plate expanding outward from the first signal via, and a second conductor plate expanding outward from the second signal via. With respect to a perpendicular bisector of a center-of-gravity line segment connecting centers of gravity of the first and second signal vias, in each of the plurality of conductor plate pairs, centers of gravity of contours of the first and second conductor plates are located on inner sides of the centers of gravity.

An elongated wired circuit board including a plurality of wires arranged in parallel, wherein the plurality of wires each includes a first linear portion extending in a first linear direction, a second linear portion extending in a second linear direction, and a connection portion, the connection portion includes a first side, a second side, a third side, and a fourth side, length y1 and length S satisfy 0<y1<S, length y1 extending from the first corner portion reaching the first widthwise other end edge of the first linear portion, and length S extending from the first widthwise other end edge of the first linear portion of one wire, and the predetermined angle θ satisfies 0<θ<1 deg.

The invention relates to an electric interface, in particular an interposer, having a first connection plane with at least one first contact surface pair, each of which has a first and second contact surface, and a second connection plane with at least one second contact surface pair, each of which has a third and a fourth contact surface. For each of a first and second contact surface pair, a first electric connection electrically connects the first contact surface of the first connection plane to the third contact surface of the second connection plane, and a second electric connection electrically connects the second contact surface of the first connection plane to the fourth contact surface of the second connection plane. The first electric connection between the first and third contact surface has a specified first geometric length, and the second electric connection between the second and fourth contact surface has a specified second geometric length, the first and second geometric length being different.

A design for printed circuit board with reduced susceptibility to common-mode noise includes a first substrate, a differential pair of signal lines with two differential transmission lines laid on the first substrate, a second substrate, a metal layer located between the first substrate and the second substrate, and a grounding layer The second substrate is located between the second substrate and the grounding layer, and a conductive structure is located in the second substrate and couples the metal layer to the grounding layer. A length of the metal layer is substantially equal to a length of each of the two differential transmission lines.

A multiple-layer circuit board has a signaling layer, an exterior layer, and a ground layer. A pair of differential signal lines implemented as strip lines are within the signaling layer, and propagate electromagnetic interference (EMI) along the signaling layer. An element conductively extends inwards from the exterior layer, and as an antenna radiates the EMI propagated by the strip lines along the signaling layer outwards from the circuit board. A defected ground structure within the ground layer has a size, shape, and a location in relation to the element to suppress the EMI propagated by the strip lines to minimize the EMI that the element radiates outwards as the antenna.

A wiring board includes a first wire, a second wire, a third wire and a fourth wire formed over a substrate and extending in a first direction respectively, the second wire being adjacent to the first wire in the first direction, and the third wire being adjacent to the first wire in a second direction orthogonal to the first direction, and the fourth wire being adjacent to the second wire in the second direction, a pair of fifth wires, a pair of sixth wires, a pair of seventh wires and a pair of eighth wires formed in the substrate and extending in the second direction respectively, a pair of ninth signal vias, a pair of tenth signal vias, a pair of eleventh signal vias and a pair of twelfth signal vias formed in the substrate and extending in a third direction orthogonal to a surface of the substrate respectively.

A high-speed transmission circuit design reduces or eliminates the presence of unwanted stub-effects and avoids uncontrolled line impedances that in existing circuits cause impedance mismatches that give rise to unwanted reflections and, ultimately, degrade signal integrity, e.g., in belly-to-belly configurations involving Quad Small Form-Factor Pluggable Double Density (QSFP DD) connectors. In various embodiments, by preventing overcrowding of signal lines, the circuit design further reduces crosstalk and increases signal integrity.

An optical module includes: an optical sub-assembly; and a flexible substrate including an insulating film, an interconnection pattern, and a spacer layer, the flexible substrate being connected to the optical sub-assembly. The insulating film has some projections, the projections protruding from a basic area in a first direction, the projections being arranged in a second direction perpendicular to the first direction, the insulating film having a flat shape with a recess between an adjacent pair of the projections. The interconnection pattern includes some pads in the basic area on a first surface of the insulating film, the pads being arranged in the second direction. The pads include some first pads adjacent to the respective projections, the pads including at least one second pad adjacent to the recess. The spacer layer is on the first surface and at each of the protrusions.

One example includes a printed circuit board (PCB) structure. The PCB structure includes a first dereferenced microstrip and a first capacitor pad contacting the first dereferenced microstrip. The PCB structure includes a second dereferenced microstrip and a second capacitor pad contacting the second dereferenced microstrip. The PCB structure also includes a capacitor including a first terminal contacting the first capacitor pad and a second terminal contacting the second capacitor pad.

A printed circuit board that includes conductive layers separated by insulation layers of dielectric material, at least one conductive layer being patterned and having at least one signal line embedded in an insulation material, whereby a conductive ground plan layer, separated by the insulation material and lying in a predetermined distance (d) from the at least one signal line includes a ground plane area associated to and extending along the at least one signal line, the conductive layer associated to and extending along the at least one signal line is provided with openings therein. Preferably the openings are spaces between conducting stripes, extending, seen from above, across the at least one signal line, the conducting stripes being integrally connected with the conductive remainder of the conductive layer.