PCB Edge Via Connection for RF Impedance Control
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Solution Overview
Problem
Existing methods for orthogonally connecting printed circuit boards, such as pin arrays and flexible circuits, are inefficient due to size constraints, cost, and assembly difficulties, especially in applications requiring precise connections for microwave frequencies.
Innovation Solution
A method involving a panel with an edge featuring a desired connection grid of exposed, electrically conductive vias, where the vias are formed in multiple layers, plated, and cut perpendicularly to create a surface for direct connection to another board without the need for pins or connectors, allowing for dense and controlled impedance connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pin arrays and sockets are used to connect boards perpendicularly, then electrical connection is achieved, but the system becomes large and expensive
Solution Approach 1:
The patent extracts the connection function from separate pins and sockets and integrates it directly into the PCB edge through exposed vias. The vias are cut to expose their inner conductive surfaces, which are then plated to create direct connection points, eliminating the need for separate pin array components and their associated sockets.
Solution Approach 2:
The patent merges the via structure with the PCB edge by cutting the board to expose via surfaces. This combines the through-hole conductor, the plating layer, and the connection interface into a single integrated feature at the board edge, reducing component count and assembly complexity.
2Reliability
If pin arrays and sockets are used for board connection, then electrical connection is established, but manufacturing precision requirements cannot be met
Solution Approach 1:
The via structure serves multiple functions simultaneously: it provides the conductive path through the board, creates the connection surface when cut and plated, and defines the connection geometry. This self-service approach eliminates the need for separate precision-machined pins and sockets, allowing standard PCB manufacturing tolerances to suffice.
3Ease of operation
If flex circuits are used to mount boards perpendicular to one another, then connection is achieved, but the flex circuit is subject to fatigue at temperature cycles
Solution Approach 1:
The patent replaces the mechanical flex circuit solution with a rigid PCB edge structure featuring exposed and plated vias. This eliminates the bending and flexing required by flexible circuits, substituting a stable, fatigue-resistant via-based connection mechanism that maintains electrical contact without mechanical stress during thermal cycling.
4Ease of operation
If flex circuits are used for perpendicular mounting, then board connection is achieved, but assembly is difficult in applications with limited spacing
Solution Approach 1:
The patent extracts the connection interface from the bulk of the PCB and places it at the edge through via exposure. This creates a compact connection profile that extends minimally from the board surface, enabling assembly in tight spaces where flex circuits would require more bulk and manipulation room.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables small, dense, and cost-effective connections with controlled impedance for RF applications, eliminating the need for pins or connectors and reducing assembly complexity.
Implementation Method 1
The cut edge of this panel, with the array of vias exposed on its surface, may then be perpendicularly connected to another thin circuit board, an aperture sheet or other panel by a ribbon bonder, a wire bonder, a welder or other suitable means.
Implementation Method 2
The several layers are then laminated to one another to form the panel, with the vias in such layers collectively forming the connection grid.
Implementation Method 3
The panel, and each of the vias, is cut in a direction substantially perpendicular to the longitudinal axes of the vias to form an edge of the panel where a surface of each of the vias is exposed.
Implementation Method 4
The exposed surface of the vias, which preferably have been cut in half, is plated with an electrically conductive material.
Data Source
AI summary
A method and apparatus is provided for forming a printed circuit board or other panel in which an array of vias are arranged in a desired connection grid within one or more layers of the board and then the board and vias are cut to form an edge of the board where a surface of the vias is exposed. The board may be orthogonally mounted on its edge to another thin circuit board or aperture sheet with the exposed surface of each via directly connected to such other board or sheet.