Waveguide E-Plane Filter Size Reduction via Ridge-Foil Segmentation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing waveguide E-plane band-pass filters are large and complex to manufacture, making them unsuitable for applications with size restrictions while maintaining effective frequency properties.

Innovation Solution

Incorporating a tubular, electrically conductive waveguide body with a conductive foil and at least one ridge that divides the inner volume, reducing the filter's size by up to 60% without degrading its filtering properties, by arranging the foil in mechanical contact with the ridge and optimizing the ridge's dimensions and shape.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a conventional waveguide E-plane filter is used, then the filtering properties are maintained, but the size is large and occupies excessive space

Engineering Contradiction:
Improvefilter sizeVSAvoidfiltering properties
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The waveguide body is divided into multiple sections along its longitudinal direction, with each section containing a specific number of resonator openings. This segmentation allows the filter to achieve the desired frequency filtering properties while reducing the overall size compared to conventional designs that require a single large resonating cavity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a conventional single-cavity E-plane filter design to a multi-section waveguide structure. By distributing resonator openings across multiple sections along the longitudinal direction, the design achieves size reduction while maintaining filtering performance through a different spatial arrangement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If the waveguide filter size is reduced, then space requirements are met, but manufacturing complexity increases

Engineering Contradiction:
Improvefilter sizeVSAvoidmanufacturing complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The waveguide body is divided into multiple sections along its longitudinal direction, with each section containing a specific number of resonator openings. This segmentation allows the filter to achieve the desired frequency filtering properties while reducing the overall size compared to conventional designs that require a single large resonating cavity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the geometric parameters of the waveguide structure by introducing multiple sections with different numbers of resonator openings (e.g., first section with two openings, second section with three openings). This parameter variation enables size reduction while maintaining the required filtering characteristics through modified resonating patterns.

Inventive Principle:
Principle #35Parameter changes

3Volume of moving object

If H-plane filters are used instead of E-plane filters, then the size is reduced, but the number of tuning positions increases making it costly and complicated to tune

Engineering Contradiction:
Improvefilter sizeVSAvoidtuning complexity
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The waveguide body is divided into multiple sections along its longitudinal direction, with each section containing a specific number of resonator openings. This segmentation allows the filter to achieve the desired frequency filtering properties while reducing the overall size compared to conventional designs that require a single large resonating cavity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The filter design uses fixed geometric structures (multiple sections with specific resonator openings) that inherently provide the required filtering properties without requiring complex tuning mechanisms. The structure serves itself by design, eliminating the need for multiple tuning positions and associated complexity.

Inventive Principle:
Principle #25Self-service

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 results in a smaller, less costly filter with improved frequency properties, including higher first harmonic and mode frequencies, reducing noise levels and the number of components needed, while maintaining or enhancing filtering performance.

Implementation Method 1

The foil or insert comprises openings which act as resonators, thereby determining the poles of the filter, and consequently also contribute to determining the passband of the filter

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

a tubular, electrically conductive waveguide body

Methodology Applied
Scientific EffectWaveguide: Waveguide

Data Source

PatentEP3266062B1Waveguide e-plane filter
Publication Date: 2018.08.22 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3266062B1 patent drawingFigure 1A~2B
  • EP3266062B1 patent drawingFigure 3A~4
  • EP3266062B1 patent drawingFigure 5A

AI summary

It is provided a waveguide E-plane band-pass filter comprising a tubular, electrically conductive waveguide body. An electrically conductive foil is arranged in the waveguide body and extending along a longitudinal direction of the waveguide body, the foil comprising a plurality of resonator openings. Furthermore, the waveguide body comprises at least one ridge protruding from an inner wall of the waveguide body and extending longitudinally along the longitudinal direction of the waveguide body. The foil is in mechanical contact with said at least one ridge and arranged to divide an inner volume of the waveguide body into two portions. It is also provided a diplexer, a radio transceiver, and a method for filtering a signal using such a filter.