Multi-Layer Waveguide Filter Structure for Low-Leakage mmWave Signals

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Solution Overview

Problem

Existing signal filters, particularly those used in millimeter wave frequency bands, face challenges such as high production costs, insertion loss, and leakage issues due to manufacturing complexities and requirements for precise conductivity, making them unsuitable for large-scale production and integration with compact antenna arrays.

Innovation Solution

A multi-layer air-filled waveguide filter with unconnected thin layers and offset apertures arranged along the perimeter outside the filter channel, which reduces leakage without the need for galvanic contact between layers, enabling cost-effective production and integration with antenna arrays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If diffusion bonding is used to produce waveguide filters, then manufacturing precision and performance are improved, but production cost increases significantly

Engineering Contradiction:
Improvemanufacturing accuracyVSAvoidproduction cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent extracts the requirement for galvanic contact between layers, eliminating the need for expensive diffusion bonding processes. By removing this constraint, the invention allows for simpler, more cost-effective manufacturing methods while maintaining filter performance through the aperture arrangement alone.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the critical parameter for leakage prevention from inter-layer conductivity to aperture geometry and arrangement. By modifying how leakage suppression is achieved (from material property to structural configuration), cost-effective manufacturing becomes feasible.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If galvanic contact between layers is required to reduce leakage, then leakage is reduced, but production cost and manufacturing complexity increase

Engineering Contradiction:
ImproveleakageVSAvoidproduction cost
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The patent removes the requirement for galvanic contact between waveguide layers. Instead of relying on conductive bonding, the invention uses offset apertures arranged in specific patterns to suppress leakage, thereby eliminating costly bonding processes while maintaining effectiveness.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical/chemical bonding system (diffusion bonding requiring galvanic contact) with an electromagnetic field-based solution using offset apertures. This substitution eliminates the need for precise mechanical alignment and bonding while achieving leakage suppression through electromagnetic field interaction.

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

3Ease of manufacture

If substrate integrated waveguide (SIW) filters are used, then production cost is reduced, but insertion loss increases

Engineering Contradiction:
Improveproduction costVSAvoidinsertion loss
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent uses air-filled waveguide channels instead of dielectric-filled SIW structures. By maintaining air as the filling medium and using offset apertures for field confinement, the invention achieves low insertion loss comparable to traditional waveguides while enabling cost-effective manufacturing through standard waveguide production methods.

Inventive Principle:
Principle #29Pneumatics and hydraulics

4Ease of manufacture

If air-filled waveguide filters with gaps between layers are used, then manufacturing is simplified, but leakage increases due to magnetic field penetration

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidleakage
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The offset apertures act as an intermediary mechanism between layers. Rather than requiring direct galvanic contact or complex bonding, the aperture arrangement creates an electromagnetic barrier that suppresses leakage through the gap, mediating the interaction between separated layers and enabling both simplicity and effectiveness.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The solution provides a cost-efficient, compact filter with reduced leakage and maintained performance, suitable for millimeter wave frequency bands, overcoming the limitations of existing technologies by eliminating the need for expensive bonding processes and achieving lower insertion losses.

Implementation Method 1

The leak suppressing structure comprises a plurality of apertures arranged with an offset between layers creating an EBG-structure (electromagnetic bandgap)

Methodology Applied
Scientific EffectElectromagnetic bandgap (EBG) structure:

Data Source

PatentEP4046234B1Multi-layer filter, arrangement, and method for production thereof
Publication Date: 2024.05.22 GAPWAVES AB
  • EP4046234B1 patent drawingFigure 1~2
  • EP4046234B1 patent drawingFigure 3~4
  • EP4046234B1 patent drawingFigure 5~6

AI summary

A multi-layer signal filter (1) comprising at least three physical layers (2a, 2b, 2c, 2d, 2e, …, 2n). Each layer has through going apertures (3) arranged with an offset to apertures (3) of at least one adjoining layer, each layer further has a filter channel opening (77) for receiving signals to be filtered. The apertures (3) are arranged along a perimeter outside the filter channel opening (77) and the apertures (3) are arranged with a central surface portion (5) increasing the edge length of the aperture (3).