Microwave Generator With Open Reflectors and Decreasing Radii

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Solution Overview

Problem

Microwave wave generator devices with oscillating virtual cathodes have low power efficiency and mediocre spectral quality due to limitations in existing designs, particularly when using reflectors, beyond which efficiency decreases.

Innovation Solution

Incorporating a series of open reflectors with decreasing radii within the cylindrical waveguide to facilitate microwave wave emission, where the first reflector has a radius equal to or greater than 0.75 times the waveguide radius and subsequent reflectors have progressively smaller radii, allowing for efficient reflection and emission of microwave waves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If reflectors are installed in the cylindrical waveguide to improve microwave wave emission, then spectral quality is improved, but power efficiency decreases beyond an optimum number of reflectors

Engineering Contradiction:
Improvespectral qualityVSAvoidpower efficiency
Core Design Contradiction:
Manufacturing precisionVSLoss of energy

Solution Approach 1:

The waveguide is segmented into multiple sections, each containing a reflector at specific positions. This segmentation allows the electromagnetic wave to be reflected and reinforced at different locations along the waveguide, improving spectral quality while controlling energy loss through optimized segment placement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the waveguide are given different properties by positioning reflectors at specific locations. The reflectors create localized regions of enhanced electromagnetic field interaction, improving spectral quality in specific zones while minimizing overall energy loss through strategic placement.

Inventive Principle:
Principle #3Local quality

2Power

If the number of reflectors is increased to improve microwave wave reflection, then wave emission is enhanced, but power efficiency decreases

Engineering Contradiction:
Improvewave emissionVSAvoidpower efficiency
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The reflectors are pre-positioned at optimized locations within the waveguide before operation. This preliminary arrangement ensures that the electromagnetic wave encounters the reflectors at optimal points, maximizing wave emission enhancement while minimizing energy loss through pre-calculated optimal positioning.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The reflectors are arranged to create continuous useful action throughout the waveguide, with each reflector contributing to wave reflection and reinforcement. This continuous arrangement ensures sustained wave emission enhancement while optimizing the number of reflectors to prevent excessive energy loss.

Inventive Principle:
Principle #20Continuity of useful action

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 significantly enhances power efficiency and maintains high-frequency stability, achieving efficiencies up to 21% compared to conventional designs, while maintaining spectral quality and reducing interaction with strong electromagnetic field regions.

Implementation Method 1

a thin sheet (frequently referred to below as 'thin anode' for simplicity)... The thin sheet is, in turn, coupled to the cylindrical waveguide... emitting a beam of electrons

Methodology Applied
Scientific EffectElectron beam transmission: Electron Beam

Implementation Method 2

When the current entering the cylindrical waveguide exceeds the space charge current limit, the electron density becomes so high that the beam can no longer propagate in the waveguide. A charge build-up, commonly referred to as a 'virtual cathode', then forms behind the thin foil.

Methodology Applied
Scientific EffectSpace charge: Electrostatics

Implementation Method 3

It is this principle of oscillation of the virtual cathode which is at the origin of a microwave wave emission

Methodology Applied
Scientific EffectMicrowave wave emission: Microwave Radiation

Implementation Method 4

The reflectors are thin walls (that is to say a few tenths of a micrometer thick), transparent to electrons and capable of reflecting the microwave wave created by the virtual cathodes

Methodology Applied
Scientific EffectElectromagnetic wave reflection: Reflection

Implementation Method 5

transparent to electrons and capable of reflecting the microwave wave

Methodology Applied
Scientific EffectElectron transparency: Electron Beam

Data Source

PatentEP2936537B1Microwave generator with oscillating virtual cathode and open reflectors
Publication Date: 2018.09.12 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2936537B1 patent drawingFigure 1~3
  • EP2936537B1 patent drawingFigure 4~7
  • EP2936537B1 patent drawingFigure 8~9

AI summary

The present invention relates to a device for generating microwaves with an oscillating virtual cathode, comprising a cathode (2), a thin anode (4) positioned at an inlet of a cylindrical waveguide (5), at least one first open reflector (9) and one last open reflector (9) located in the waveguide (5), which are transparent to electrons and capable of reflecting a microwave created by at least one virtual cathode generated in the waveguide (5), and a plurality of open reflectors (9) between the first and last open reflector (9) such that one reflector from the plurality has a radius RR(i+1) less than or equal to a radius RRi of a reflector from the immediately preceding plurality and the last open reflector (9) having a radius RRN less than a radius RR1 of the first open reflector.