Waveguide Dielectric Perturbation for Side Lobe Reduction

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Solution Overview

Problem

Existing waveguides with constant cross-sectional areas face challenges in reducing side lobe energy, as they cannot easily convert energy from a dominant propagation mode to a higher order mode without modifying the waveguide wall, which is costly and impractical for systems already in place.

Innovation Solution

Incorporating a dielectric material with varying cross-sectional area along a portion of the waveguide, which emulates a perturbation in the waveguide wall to convert energy from a dominant propagation mode to a secondary mode without altering the waveguide's cross-sectional area, using a mode transition portion and a mode combiner portion to achieve phase difference and cancel longitudinal edge currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If the waveguide wall is modified to convert energy from dominant mode to higher order mode, then side lobe energy is reduced, but manufacturing cost and structural complexity increase

Engineering Contradiction:
Improveside lobe energyVSAvoidwaveguide modification cost
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

A dielectric member is introduced as an intermediary element inside the waveguide to achieve mode conversion. This dielectric member acts as a mediator that transforms the dominant propagation mode to higher order modes without requiring any modification to the waveguide wall structure, thereby reducing side lobe energy while avoiding costly manufacturing changes

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The dielectric member utilizes changes in dielectric properties (permittivity) along its length to achieve mode conversion. By varying the dielectric constant or physical dimensions of the dielectric member, the patent transforms electromagnetic energy between different propagation modes, effectively reducing side lobe radiation without structural modifications to the waveguide

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If the cross-sectional area of the waveguide is varied to convert modes, then energy conversion from dominant to higher order mode is achieved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improveside lobe energyVSAvoidwaveguide structure
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The dielectric member serves as an intermediary that enables mode conversion within a constant cross-sectional waveguide. Instead of varying the waveguide's cross-sectional area, the dielectric member's varying dielectric properties provide the necessary perturbation to convert modes, simplifying the overall device structure

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the dielectric parameter (permittivity) of the dielectric member along its length to achieve mode conversion. This parameter change within the dielectric material provides an alternative to changing the geometric parameters of the waveguide itself, thereby maintaining structural simplicity

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If longitudinal edge currents are canceled to reduce side lobe energy, then radiation pattern is enhanced, but additional components or modifications are required

Engineering Contradiction:
Improveside lobe energyVSAvoidwaveguide components
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The dielectric member acts as a single integrated intermediary that achieves both mode conversion and longitudinal current cancellation simultaneously. By strategically positioning and dimensioning the dielectric member, the patent eliminates the need for separate components to address these two related issues

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent merges the functions of mode conversion and current cancellation into a single dielectric member structure. This combined approach achieves enhanced radiation patterns by simultaneously transforming propagation modes and canceling longitudinal edge currents, reducing the number of separate components needed

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 approach allows for efficient mode conversion in waveguides with constant cross-sectional areas, reducing side lobe energy by converting energy from the dominant propagation mode to the secondary mode, thereby enhancing the radiation pattern without the need for costly modifications to the waveguide structure.

Implementation Method 1

convert energy from a dominant propagation mode to a secondary mode

Methodology Applied
Scientific EffectMode conversion:

Implementation Method 2

Incorporating a dielectric material with varying cross-sectional area along a portion of the waveguide

Methodology Applied
Scientific EffectDielectric material interaction: Dielectric

Implementation Method 3

receiving electromagnetic energy at a first end of the waveguide and propagating the electromagnetic energy along a length of the waveguide to a second end

Methodology Applied
Scientific EffectWaveguide propagation: Waveguide

Data Source

PatentEP3276740B1Multi-mode waveguide
Publication Date: 2020.11.04 THE BOEING CO
  • EP3276740B1 patent drawingFigure 1A
  • EP3276740B1 patent drawingFigure 1B~1D
  • EP3276740B1 patent drawingFigure 1E

AI summary

An apparatus includes a waveguide (100). The waveguide (100) includes a waveguide wall (102) having a shape associated with a dominant propagation mode. The waveguide (100) includes a first dielectric material (110) having a cross-sectional area that varies along a length of a portion (106) of the waveguide (100).