RF Coupling via Slot Aperture in Ground Plate

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional radio frequency connections between transmission lines on either side of a ground plate are costly and prone to signal loss or distortion due to mechanical misalignment and the need for expensive, tightly toleranced co-axial connectors.

Innovation Solution

A radio frequency connection arrangement utilizing a ground plate with an aperture having a slot, where the first transmission line is printed on a thin polyester film with an air gap and supported by raised sections, allowing signal coupling without electrically conductive connections, thus avoiding intermodulation distortion and maintaining mechanical support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If co-axial radio frequency connectors are used to connect transmission lines through a ground plate, then a good electrical connection is achieved, but the manufacturing cost increases and mechanical misalignment causes signal loss

Engineering Contradiction:
Improveradio frequency connection qualityVSAvoidmanufacturing cost and complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the signal coupling function from the ground plate itself by creating an aperture with a slot that allows electromagnetic field coupling. This removes the need for co-axial connectors while maintaining RF connection quality, as the slot in the ground plate directly enables signal transfer between transmission lines on opposite sides.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The aperture with a slot acts as an intermediary structure that mediates the RF signal transfer between transmission lines on opposite sides of the ground plate. Instead of direct connector contact, the slot provides a controlled electromagnetic coupling path that maintains signal integrity while simplifying the connection mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of energy

If co-axial connectors with tight mechanical tolerances are used, then signal loss is reduced, but the device complexity and manufacturing precision requirements increase

Engineering Contradiction:
Improvesignal lossVSAvoidmechanical tolerance requirements
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical contact system of co-axial connectors with an electromagnetic field coupling system through the slot aperture. This substitution eliminates the need for tight mechanical tolerances and precise alignment, as the RF signal couples through the slot via electromagnetic fields rather than requiring direct physical contact between precision-machined connector surfaces.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs a simpler, more robust aperture structure that can be manufactured with standard tolerances rather than requiring expensive, precision-machined co-axial connectors. The slot aperture is a permanent structural feature of the ground plate that tolerates manufacturing variations better than precision connectors.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Strength

If a thick ground plate is used to provide mechanical support, then structural strength is improved, but the aperture design becomes more challenging for RF coupling

Engineering Contradiction:
Improvemechanical support capabilityVSAvoidaperture design complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent segments the aperture into specific geometric features (slot configuration within the aperture) that optimize RF coupling while maintaining compatibility with thick ground plate structures. The slot dimensions and orientation are specifically designed to create effective electromagnetic coupling paths that work well with the mechanical support requirements of thick ground plates.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent optimizes the slot dimensions, orientation, and position within the aperture to achieve effective RF coupling through thick ground plates. By carefully controlling the slot width, length, and placement relative to the transmission lines, the design maintains low signal loss while accommodating the mechanical strength requirements of thicker ground plate structures.

Inventive Principle:
Principle #35Parameter changes

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 low-loss radio frequency coupling, reduces manufacturing costs by avoiding co-axial connectors, and is tolerant of mechanical misalignment, ensuring efficient signal transfer across the ground plate.

Implementation Method 1

slot-coupled interconnects for coupling radio frequency signals between layers of a multi-layer printed circuit board, through an aperture in a ground plane

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3257101B1Radio frequency connection arrangement
Publication Date: 2021.05.26 CAMBIUM NETWORKS
  • EP3257101B1 patent drawingFigure 1~2
  • EP3257101B1 patent drawingFigure 3~4
  • EP3257101B1 patent drawingFigure 5

AI summary

A radio frequency transmission arrangement comprises a ground plate (13) having an aperture comprising a slot (14) with an elongate cross-section and substantially parallel sides, and a first (12, 11) and second (17, 18) transmission line. The thickness of the ground plate (t) is greater than a width of the slot (w). The first transmission line comprises a first elongate conductor (12) on a first side of the ground plate (13) and has an end terminated with a first termination stub (11). The second transmission line comprises a second elongate conductor (17) on the opposite side of the ground plate and has an end terminated with a second termination stub (18). The first transmission line is arranged to cross the slot at a point adjacent to the first termination stub (11), and the second transmission line is arranged to cross the slot at a point adjacent to the second termination stub (18).