Broadside PCB RF Interconnect for Connector-Less Gap Coupling

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Solution Overview

Problem

Existing RF signal transmission technologies require complex and expensive connectors for interconnects between printed circuit boards, which are difficult to manufacture and align, leading to reliability concerns and high costs, especially in large-scale applications like electronically steered arrays.

Innovation Solution

The use of broadside coupling features on circuit board traces with terminal portions aligned in proximity, along with a dielectric material and magnetic elements, enables contactless RF energy transfer across a gap, eliminating the need for physical connectors and reducing assembly complexity and costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If blind mate connectors are used to transmit RF signals between PCBs, then signal transmission is achieved, but alignment difficulty and assembly complexity increase

Engineering Contradiction:

Improveconnection reliabilityVSAvoidalignment precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical connector systems with electromagnetic field-based energy transfer. Broadside coupled traces on opposing PCB surfaces create capacitive coupling that transfers RF signals without physical contact, eliminating alignment and mating force requirements while maintaining signal transmission reliability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a dielectric material as an intermediary between the broadside coupled traces on opposing PCBs. This dielectric layer enables capacitive coupling and RF energy transfer across the gap while providing mechanical spacing and electrical isolation, solving both alignment and signal transmission requirements

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If multiple connectors are used for high-density RF interconnects, then signal transmission capacity increases, but cost and assembly complexity increase

Engineering Contradiction:

Improvenumber of connectionsVSAvoidconnector complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent merges multiple individual connector functions into a single integrated broadside coupling interface. By arranging traces in parallel on opposing PCB surfaces with capacitive coupling, the system achieves high-density RF interconnect functionality without requiring multiple discrete connectors, thereby reducing assembly complexity and cost

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The broadside coupling structure serves multiple functions simultaneously: it provides RF signal transmission, mechanical spacing between PCBs, electrical isolation through the dielectric, and alignment reference. This multi-functionality eliminates the need for separate connectors and alignment features

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If blind mate connectors are used, then RF signal transmission is achieved, but assembly time and manufacturing risk increase

Engineering Contradiction:

Improveconnection reliabilityVSAvoidassembly speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The PCBs are manufactured with broadside coupling traces and dielectric structures pre-integrated into the board design. This preliminary integration eliminates the need for post-assembly connector installation and alignment procedures, significantly reducing assembly time and manufacturing risk while maintaining reliable RF signal transmission

Inventive Principle:

Principle #10Preliminary action

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

This solution provides a cost-effective, high-performance RF interface with reduced manufacturing risks and assembly time, minimizing signal loss and noise while maintaining desired impedance and bandwidth characteristics.

Implementation Method 1

broadside coupling features of terminal portions of the circuit board traces configured to convey radio frequency signals over a gap between the terminal portions

Methodology Applied

Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Implementation Method 2

a dielectric material positioned within the gap

Methodology Applied

Scientific EffectDielectric: Dielectric

Implementation Method 3

magnetic elements configured to magnetically couple and planarly align corresponding pairs of broadside coupling features of the circuit boards

Methodology Applied

Scientific EffectMagnetic coupling: Magnetism

Data Source

PatentUS12069798B1Broadside coupled radio frequency interconnect

Publication Date: 2024.08.20 LOCKHEED MARTIN CORP

AI summary

Enhanced components and assemblies for connector-less radio frequency (RF) interconnect systems are provided. One example includes two circuit boards each with a broadside coupling feature comprising a tapered circuit board trace having a terminal portion. The circuit boards are positioned in close proximity to establish a desired gap, and a dielectric material is positioned within the gap between circuit boards. The broadside coupling features of the circuit boards are then configured to convey RF signals over the gap without electrical contact.