Abstract: A technique for reducing the number of layers in a multilayer circuit board is disclosed. The multilayer circuit board has a plurality of electrically conductive signal layers for routing electrical signals to and from at least one electronic component mounted on a surface of the multilayer circuit board. In one embodiment, the technique is realized by forming a first plurality of electrically conductive vias in the multilayer circuit board extending from the surface of the multilayer circuit board to a first of the plurality of electrically conductive signal layers, wherein the first plurality of electrically conductive vias are arranged so as to form a channel in a second of the plurality of electrically conductive signal layers beneath the first plurality of electrically conductive vias.

Abstract: A midplane board adapted for use in an electronic equipment shelf is provided. The midplane board includes a first surface having a plurality of contact elements adapted to engage corresponding contact elements on a first circuit board. The midplane board also includes a second surface in opposite relationship with the first surface. The second surface has a plurality of contact elements adapted to engage corresponding contact elements on a second circuit board in such a manner that at least a portion of a side of the first circuit board is opposed to at least a portion of a side of the second circuit board. The midplane includes at least one signal connection path including a buried via suitable for establishing a connection between a contact element on the first surface and a contact element on the second surface. The contact elements on the first surface define a first pattern while the contact elements on the second surface define a second pattern.

Abstract: A cable card having increased cable connector density is provided. The cable card has a non-planar surface and, therefore, more surface area than a planar cable card having the same outside dimensions. The increased surface area of the non-planar surface permits more connectors of a given size to be located on the cable card.

Abstract: A technique for improving electrical signal performance in multilayer circuit boards by eliminating the need for electrically conductive vias is disclosed. In one embodiment, the technique is realized as an improved multilayer circuit board having an electrically conductive signal layer disposed beneath at least one dielectric layer. The improvement comprises a cavity in the multilayer circuit board extending through the at least one dielectric layer so as to expose at least a portion of the electrically conductive signal layer within the cavity. The cavity is sized to accommodate an electronic component therein such that the electronic component makes electrical contact with the exposed portion of the electrically conductive signal layer, thereby eliminating the need for an electrically conductive via electrically connected to the electrically conductive signal layer and formed through the at least one dielectric layer or any other layer of the multilayer circuit board.

Abstract: An improved electrical interconnection between a first circuit board and a second circuit board is provided. In one embodiment, the first circuit board has a substantially rigid circuit portion having a plurality of circuit layers, including a first signal layer, and a first interconnection portion, including the first signal layer, for mating with a second interconnection portion of the second circuit board. The first circuit board also includes a flexible portion, including the first signal layer, for connecting the substantially rigid circuit portion to the first interconnection portion. The flexible portion allows the first interconnection portion to be oriented substantially perpendicular to the substantially rigid circuit portion such that a mating of the first interconnection portion with the second interconnection portion results in a substantially orthogonal electrical interconnection arrangement between the first circuit board and the second circuit board.

Abstract: A technique for increasing electronic component density on circuit boards is disclosed. In one embodiment, the technique is realized as an improved electronic circuit board for enabling the stacking of electronic components. The electronic circuit board has an electrically conductive signal layer formed on a dielectric layer, wherein the electrically conductive signal layer has a plurality of electrically conductive pads formed therein. The improvement comprises a cavity in the electronic circuit board extending through the electrically conductive signal layer and the dielectric layer.

Abstract: In printed wiring boards, crosstalk can occur by the electrical coupling between nearby signal lines in a given layer. This source of noise degrades signal quality and is a major limiting factor in communication systems performance, especially at high frequencies. To eliminate crosstalk between copper signal lines in a printed wiring board, a metal shield is formed around each signal trace from the transmit end to the receive end. The metal shield is built from a microstrip or stripline in the printed wiring board by cutting grooves from the surface on both sides of the signal line, through the dielectric material to the underlying ground plane, thereby exposing the ground metal all along the bottom of the channel. Preferably, the grooves are formed using techniques adapted from microvia technology. Metallization is then applied to the top surface and the grooves (side walls and bottom) resulting in the formation of a complete metal shield around the signal line comparable to that of a coaxial cable.

Abstract: A technique for increasing electronic component density on multilayer printed circuit boards is disclosed. In one embodiment, the technique is realized as an improved multilayer circuit board for enabling the stacking of electronic components. The multilayer circuit board has a first electrically conductive layer and a second electrically conductive layer separated by at least one dielectric layer. The improvement comprises a cavity in the multilayer circuit board extending through the first electrically conductive layer and the at least one dielectric layer so as to expose at least a portion of the second electrically conductive layer within the cavity.

Abstract: A technique for connecting signal tracks within a multi-layer substrate is disclosed. In one embodiment, the technique is realized by providing an opening in a substrate and fitting an inserted component into the opening. The inserted component comprises a dielectric block mounted to a lead frame. The lead frame is conductive such that a signal layer formed between the inserted component and the substrate connects signal tracks on multiple signal layers of the substrate.

Abstract: A technique for coupling a signal between a first circuit board and a second circuit board. In one embodiment, the first circuit board has a first signal conductor formed therein, and the second circuit board has a second signal conductor formed therein. Also, the first signal conductor is shielded by a first electrically conductive shield, and the second signal conductor is shielded by a second electrically conductive shield. In this embodiment, the technique is realized by forming a first opening in the first electrically conductive shield so as to expose the first signal conductor in the first circuit board, and forming a second opening in the second electrically conductive shield so as to expose the second signal conductor in the second circuit board. The first circuit board and the second circuit board are then positioned such that the first opening and the second opening are aligned and a signal propagating along the first signal conductor is coupled to the second signal conductor.

Abstract: A technique for reducing the number of layers in a multilayer circuit board is disclosed. In one embodiment, the technique is realized by forming a first plurality of electrically conductive vias in the multilayer circuit board extending from the surface of the multilayer circuit board to a first of the plurality of electrically conductive signal layers, wherein the first plurality of electrically conductive vias are arranged so as to form a channel in a second of the plurality of electrically conductive signal layers beneath the first plurality of electrically conductive vias. A first plurality of electrical signals are routed on the first of the plurality of electrically conductive signal layers. A second plurality of electrical signals are routed on the second of the plurality of electrically conductive signal layers in the channel formed in the second of the plurality of electrically conductive signal layers.