Waveguide Substrate Choke Structure for Signal Leakage

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Solution Overview

Problem

Conventional waveguide connecting structures using metallic parts result in increased weight, cost, and thickness, and face challenges in forming accurate hollow waveguides due to the complexity of layering substrates, leading to signal leakage and increased transmission loss.

Innovation Solution

A connecting structure featuring a first substrate with a hollow waveguide and a second substrate with a converter and transmission line, where a choke structure surrounds the hollow waveguide to prevent signal leakage, and the substrates are fixed using an adhesive outside the choke structure, allowing for separate fabrication and accurate thickness control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metallic parts are used in waveguide connecting structures, then connection reliability is improved, but weight and cost increase

Engineering Contradiction:
Improveconnection reliabilityVSAvoidweight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces the traditional mechanical connection structure (metallic plates and screws) with an integrated substrate structure. The waveguide and connecting portions are formed as single-piece or multi-layered substrate integrations, eliminating the need for separate metallic connection parts. This substitution reduces weight while maintaining connection reliability through precise substrate fabrication and integrated design.

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

2Reliability

If metallic plates are used to form waveguide converters, then transmission characteristics are improved, but apparatus thickness increases

Engineering Contradiction:
Improvetransmission characteristicsVSAvoidapparatus thickness
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent merges the waveguide converter function with the substrate structure itself. The connecting portions are integrated into the substrate layers, allowing the waveguide to transition between layers without requiring additional metallic plates. This merging reduces apparatus thickness while maintaining transmission characteristics through careful design of the substrate layers and waveguide geometry.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If substrates are layered to form hollow waveguides, then integration is improved, but manufacturing precision deteriorates due to complexity

Engineering Contradiction:
ImproveintegrationVSAvoidmanufacturing precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent segments the waveguide structure into distinct substrate layers, each with specific functions. The first substrate contains the waveguide, while subsequent substrates contain connecting portions and transmission lines. This segmentation allows each layer to be manufactured and controlled separately, improving manufacturing precision while achieving high integration. The segmented approach also facilitates assembly and quality control.

Inventive Principle:
Principle #1Segmentation

4Reliability

If choke slots are formed to surround hollow waveguide, then signal leakage is prevented, but manufacturing complexity increases

Engineering Contradiction:
Improvesignal leakage preventionVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the choke slot structure with the substrate layers. The choke slots are formed as conductive patterns on the substrate surfaces, integrating the signal containment function into the existing substrate structure. This approach prevents signal leakage while avoiding the need for separate choke components, thereby reducing manufacturing complexity compared to traditional metallic choke structures.

Inventive Principle:
Principle #5Merging (Combining)

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 configuration suppresses high-frequency signal leakage and facilitates the formation of hollow waveguides, achieving low-loss transmission and reducing the complexity of substrate layering.

Implementation Method 1

a choke structure to shield a leak of the high frequency signal is arranged around the hollow waveguide

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Data Source

PatentEP2426782B1Waveguide conversion portion connection structure, method of fabricating same, and antenna device using this connection structure
Publication Date: 2020.06.10 MITSUBISHI ELECTRIC CORP
  • EP2426782B1 patent drawingFigure 1~2
  • EP2426782B1 patent drawingFigure 3~4
  • EP2426782B1 patent drawingFigure 5

AI summary

A connecting structure of a waveguide converter includes a circuit substrate (2) in which a hollow waveguide (11) that propagates a high frequency signal is formed in a pierced manner; and an antenna substrate (4) that is layered on the circuit substrate (2), and in which a converter (22) that is arranged at a connecting point with the hollow waveguide (11) and a strip line (16) that extends from the converter (22) and that propagates the high frequency signal are provided. A choke circuit (21) to shield a leak of the high frequency signal is arranged around the hollow waveguide (11) on a surface of the circuit substrate (2) opposing to the antenna substrate (4) so as to surround the hollow waveguide (11) keeping a predetermined interval from the hollow waveguide (11), and the circuit substrate (2) and the antenna substrate (4) are fixed to each other by adhesive (20) that is arranged at a position outside the choke circuit (21), between the substrates.