A method for designing a layout of a card edge connector and a server a card are provided. The method includes: determining, based on a type of a GND pin of a card edge connector and space between the card edge connector and GND vias, the number of GND vias connected to the GND pin to maximize the number of the GND vias connected to the GND pin; connecting each GND pin to all the GND vias that match with said GND pin to form one signal return path; and minimizing a length of the signal return path by setting all the GND vias that match with said GND pin in close proximity to said GND pin in the signal return path.

A transmission circuit board includes a bendable area, a first transmission areas, and a second transmission areas. The first and second transmission areas are connected to the bendable area. The inner circuit substrate board further includes a substrate layer and an inner circuit layer formed on the substrate layer and including a first signal circuit. The transmission circuit board further includes a first dielectric layer formed on the inner circuit layer, a first outer circuit layer formed on the first dielectric layer, a first protecting layer formed on the first outer circuit layer, and a first shielding layer formed on the first protecting layer. The first dielectric layer lies the first and second transmission areas. Two ends of the first signal circuit are connected to the first outer circuit layer. The first shielding layer is connected to the first outer circuit layer and lies the bendable area.

An apparatus comprising a stack of printed circuit board (PCB) layers having a primary longitudinal structure forming a radio frequency (RE) via including a principal tuning section (223) and a constant longitudinal structure (227) along a conductive column support (255) journaled through the layers in the via. The principal section (221) comprising a first tuning sub-assembly (229 A) in a first portion of the RE via above the longitudinal structure (227) and at an entrance of the primary longitudinal structure (221) and comprising a first set of pad, anti-pad pairs (445, 545, 645) tuned to receive an RE band. A second principal tuning sub-assembly (229B) in a second portion of the via below the longitudinal structure (227) and at an exit of the primary longitudinal structure and comprising a second set of pad, anti-pad pairs (445, 545, 645) tuned to receive the band and mirroring the first set of pairs.

In a multilayer board, a transmission line includes layers including a first insulator layer, a first joining material layer in contact with a first surface of the first insulator layer, and a second joining material layer in contact with a second surface of the first insulator layer. A signal conductor of the transmission line is on the first surface of the first insulator layer, a relative permittivity of the second joining material layer is lower than a relative permittivity of the first joining material layer, and an adhesion strength between the first insulator layer and the first joining material layer is higher than an adhesion strength between the first insulator layer and the second joining material layer.

The present invention provides a wiring structure of high frequency signal wires and a PCB board including the wiring structure of high frequency signal wires. A test part is formed by extending a high frequency signal wire from a connection end connected with a solder pad, and a test window corresponding to a position of the test part is provided on a copper foil which covers the solder pad and the test part, to expose the high frequency signal wire, such that a high frequency signal transmitted via the high frequency signal wire can be directly tested at the test window. Thus, circular test points used in the prior art can be removed, to effectively solve the problem of insufficient space on a PCB; accordingly, lengths of the high frequency signal wires become more precise, so as to ensure a synchronization of transmission of the high frequency signal wires.

An imaging apparatus according to the present invention includes a lens unit including an image sensor, and configured to be rotatable about a tilt rotation axis, a rotating unit configured to be rotatable about a pan rotation axis, a non-rotating unit to which the rotating unit is rotatably attached, and a flexible printed circuit configured to connect the lens unit with the non-rotating unit. The flexible printed circuit includes an arc-shaped first portion coaxial with the pan rotation axis in a plane perpendicular to the pan rotation axis, and an arc-shaped second portion coaxial with the tilt rotation axis in a plane perpendicular to the tilt rotation axis. The first portion is bent around an axis orthogonal to the pan rotation axis.

A radio IC device includes an electromagnetic coupling module includes a radio IC chip arranged to process transmitted and received signals and a feed circuit board including an inductance element. The feed circuit board includes an external electrode electromagnetically coupled to the feed circuit, and the external electrode is electrically connected to a shielding case or a wiring cable. The shielding case or the wiring cable functions as a radiation plate. The radio IC chip is operated by a signal received by the shielding case or the wiring, and the answer signal from the radio IC chip is radiated from the shielding case or the wiring cable to the outside. A metal component functions as the radiation plate, and the metal component may be a ground electrode disposed on the printed wiring board.

A resin composition and a use thereof are provided. The resin composition includes, in parts by weight, 100 parts of an alkali-soluble resin, 5-30 parts of acrylate monomers, 0.1-10 parts of photoinitiator, 10-30 parts of a first epoxy resin and 0-15 parts of a second epoxy resin. The first epoxy resin is a low-dielectric epoxy resin with a dielectric constant of <3.5 and the second epoxy resin is different from the first epoxy resin. With the addition of the low epoxy resin with the dielectric constant of >3.5, and by adjusting the ratio of the components, the resin composition significantly reduces the dielectric constant and dielectric loss, the dielectric constant is reduced to 3.0 or less, and the dielectric loss is reduced to 0.008 or less.

A flexible substrate (1) is bent at a bending part (2). A dielectric plate (3) has first and second main surfaces opposite to each other. A high-frequency signal line (4) is provided on the first main surface of the dielectric plate (3). A ground conductor (5) is provided on the second main surface of the dielectric plate (3). The high-frequency signal line (4) and the ground conductor (5) form a micro strip line. A local absent part (6) facing the high-frequency signal line (4) is provided on the ground conductor (5) only at the bending part (2).

A printed circuit board according to an embodiment of the present invention includes a core layer and a circuit wiring layer disposed on a top surface of the core layer. The core layer is spaced apart from the circuit wiring layer and includes through-holes formed around the circuit wiring layer. Flexibility of the printed circuit board may be enhanced by the through-hole to obtain bending stability.