Waveguide Filter With Overlapping Resonant Cavities

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Solution Overview

Problem

The complexity and increased circuit loss associated with waveguide filters when applied across multiple layers of circuits require a solution to simplify the circuit structure and reduce transition complexities.

Innovation Solution

A waveguide filter design featuring a first waveguide at an upper layer and a second waveguide at a lower layer, isolated by a metal isolation layer, with overlapping circular resonant cavities and a coupling slot at the metal isolation layer, allowing for direct coupling without additional transition structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If waveguide filters are applied across multiple layers of circuits, then the frequency-selecting function is achieved, but the circuit structure complexity and circuit loss increase due to extra transition structures

Engineering Contradiction:
Improvefrequency-selecting functionVSAvoidcircuit structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies nesting by placing resonant cavities from different waveguides at different layers into overlapping spatial positions. The first resonant cavity from the first waveguide and the second resonant cavity from the second waveguide are positioned to overlap, with the second cavity partially penetrating through the metal isolation layer into the space occupied by the first cavity. This nested arrangement allows direct coupling between layers through the coupling slot without requiring additional transition structures, thereby reducing circuit structure complexity while maintaining the frequency-selecting function.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Adaptability or versatility

If waveguide filters are applied across multiple layers of circuits, then the frequency-selecting function is achieved, but circuit loss increases due to extra transition structures

Engineering Contradiction:
Improvefrequency-selecting functionVSAvoidcircuit loss
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The nested cavity arrangement eliminates the need for additional transition structures between layers, thereby reducing the number of interfaces where energy loss occurs. By allowing resonant cavities to overlap and couple directly through the metal isolation layer via a coupling slot, the patent minimizes energy loss that would otherwise be introduced by complex transition structures.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Ease of operation

If traditional multi-layer waveguide adaptation is used, then inter-layer connection is achieved, but the circuit structure becomes more complex requiring extra transition structures

Engineering Contradiction:
Improveinter-layer connectionVSAvoidcircuit structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent implements inter-layer connection by nesting resonant cavities from different waveguides in overlapping positions. The metal isolation layer with a coupling slot enables direct electromagnetic coupling between the nested cavities, providing a simple and elegant solution for inter-layer connection without requiring complex transition structures such as waveguide bends, adapters, or additional coupling elements.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 design simplifies the circuit structure and reduces circuit loss by enabling direct adaptation between waveguides across layers through the coupling slot, maintaining high Q-value and selectivity performance.

Implementation Method 1

a coupling slot is disposed at the metal isolation layer in an overlapping area

Methodology Applied
Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Implementation Method 2

the first waveguide forms a first resonant cavity, the second waveguide forms a second resonant cavity

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP2955782B1Waveguide filter
Publication Date: 2018.03.21 HUAWEI TECH CO LTD
  • EP2955782B1 patent drawingFigure 1~2
  • EP2955782B1 patent drawingFigure 3~4
  • EP2955782B1 patent drawingFigure 5

AI summary

An embodiment of the present invention discloses a waveguide filter, which relates to wireless communications technologies. The waveguide filter of the present invention is formed by means of adaptation between waveguides at different layers of circuits, where a circuit structure is relatively simple. The waveguide filter of the present invention includes a first waveguide at an upper layer and a second waveguide at a lower layer, where the first waveguide and the second waveguide are isolated from each other by a metal isolation layer, the first waveguide forms a first resonant cavity, the second waveguide forms a second resonant cavity, the first resonant cavity and the second resonant cavity overlap each other, and a coupling slot is disposed at the metal isolation layer in an overlapping area.