Microwave Beam Deflection Mirrors for Multi-Frequency Absorption Loads
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Solution Overview
Problem
Existing microwave absorption loads designed for 170 GHz frequencies face challenges in adapting to different frequencies or multi-frequency operations, requiring significant redesign and increased costs, which limits their applicability in fusion laboratories needing varied frequencies.
Innovation Solution
A compact microwave absorption apparatus using a deflection device with off-axis converging mirrors to redirect scattered radiation, allowing the use of loads designed for specific frequencies without structural modifications, and accommodating a range of frequencies from 30 to 300 GHz.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If loads are designed for specific frequencies (e.g., 170 GHz), then absorption performance at that frequency is optimized, but adaptability to other frequencies is lost
Solution Approach 1:
The system is divided into two independent segments: a frequency-specific load (optimized for 170 GHz) and a frequency-agile deflection device (mirrors and waveguide). This segmentation allows the load to maintain optimal absorption performance at its design frequency while the deflection device handles frequency adaptation, resolving the contradiction between specialized performance and versatility.
Solution Approach 2:
The deflection device acts as an intermediary between the microwave source and the frequency-specific load. By using mirrors and waveguide components that can deflect microwaves across a broad frequency range (30-300 GHz), it mediates between the need for frequency-specific optimization and the requirement for frequency agility, allowing the load to operate at its optimal frequency while the system as a whole adapts to different frequencies.
2Adaptability or versatility
If load structure is modified to accommodate different frequencies, then frequency versatility is improved, but development costs and loss of know-how increase
Solution Approach 1:
The frequency adaptation function is extracted from the load structure itself and placed into a separate deflection device. This extraction allows the load to remain a simple, well-understood structure optimized for a single frequency, while the complex frequency-adaptation functionality resides in the deflection device using standard mirrors and waveguide components, thereby avoiding the need to redesign and re-test the load for each frequency.
Solution Approach 2:
The deflection device is designed with universal components (mirrors, waveguide) that can handle a broad frequency range (30-300 GHz). This multi-functional deflection device replaces the need for multiple frequency-specific loads, providing frequency versatility without requiring modifications to the load structure itself, thus avoiding increased development costs and loss of specialized know-how.
3Reliability
If scattered radiation is allowed to diffuse outwards from the load opening, then low reflection is achieved, but measurement accuracy and safety are reduced
Solution Approach 1:
The scattered radiation that would normally diffuse harmfully outwards is converted into a beneficial signal by the deflection device. The mirrors and waveguide capture this scattered radiation and redirect it in a controlled manner, allowing it to be measured accurately while preventing it from causing safety issues. This transforms the harmful scattered radiation into a useful measurement signal, simultaneously improving measurement accuracy and maintaining safety while preserving low reflection performance.
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
Enables the use of microwave absorption loads across multiple frequencies without redesigning existing structures, reducing reflection, improving thermal management, and enhancing safety and measurement accuracy in fusion reactors.
Implementation Method 1
A compact microwave absorption apparatus using a deflection device with off-axis converging mirrors to redirect scattered radiation
Implementation Method 2
Microwave beams carry high power that is supplied by sources, e.g. gyrotrons
Implementation Method 3
This high power is injected into the plasma to heat it by means of a wave-particle absorption process
Data Source
AI summary
An apparatus for absorbing microwave beams may include: a load; and a deflection device. The load may be a bolometric device, including: a first body with a first cavity including a first opening for entry of a microwave beam; and a scattering element configured to reflect the microwave beam toward an internal surface of the first cavity. The deflection device may include a second body comprising a second cavity that includes second and third openings. The second opening may be connected with the first opening. The third opening may connect with transmission lines to transport the microwave beams to the deflection device. The second cavity may include a first converging mirror configured to intercept the microwave beam; and a second converging mirror configured to deflect the microwave beam toward the first opening. An optical path length between the converging mirrors is substantially equal to a sum of their focal lengths.