Dielectric Lens Mode Generator for Radar Level Gauge
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Solution Overview
Problem
Existing radar level gauge systems face challenges with manufacturing high-frequency mode generators due to extreme tolerances and structural strength issues, especially in wave guiding structures like still pipes, which affect accuracy and ease of manufacturing.
Innovation Solution
A radar level gauging system with a mode generator using a lens in the wave guiding structure that converts electromagnetic waves from a first propagation mode to a second, featuring a convex bottom surface and a flat upper surface with a spiral pattern, providing stability and focusing effects without the need for thin, fragile components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a circuit board with a patch array feeder is used to generate H01 mode at high frequencies, then the desired circumferential electrical field is created, but the manufacturing becomes difficult due to extreme tolerances
Solution Approach 1:
The patent replaces the complex mechanical circuit board with patch array feeder with a simpler optical-like lens system. The lens, made of dielectric material with specific refractive index, uses optical principles (refraction and reflection) instead of complex electrical circuitry to generate the desired H01 mode circumferential electrical field at high frequencies, thereby eliminating extreme manufacturing tolerance requirements
Solution Approach 2:
The patent changes the fundamental operating parameters by using a lens with specific refractive index properties and geometric curvature parameters instead of electrical circuit parameters. This allows the system to achieve the same H01 mode generation function through optical parameter optimization rather than mechanical precision manufacturing
2Measurement precision
If thin plastic sheets with curved surfaces are used in the mode generator, then the desired field transformation is achieved, but the structural strength and stability are compromised
Solution Approach 1:
The patent employs composite material construction for the lens, combining dielectric material with embedded conducting patterns (spiral and radial). This composite structure provides both the optical properties needed for field transformation and the mechanical strength required for structural stability, eliminating the need for thin, fragile plastic sheets
Solution Approach 2:
The patent uses a lens with curved surfaces (spheroidal or aspherical geometry) to achieve the desired field transformation through optical refraction and reflection principles. The curvature is optimized for electromagnetic wave focusing and mode conversion while maintaining structural integrity, avoiding the need for thin flat sheets that would lack strength
3Measurement precision
If complex curved surfaces with conducting patterns are used, then H01 mode conversion is achieved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent replaces complex mechanical structures with conducting patterns on thin substrates with a monolithic lens structure having integrated conducting patterns. This unified optical-mechanical design reduces the number of separate components and assembly steps, thereby reducing overall device complexity while maintaining H01 mode conversion functionality
Solution Approach 2:
The patent merges multiple functional elements (field transformation, focusing, and mode conversion) into a single lens component with integrated conducting patterns. This consolidation eliminates the need for separate curved surfaces and conducting pattern layers, simplifying the overall device structure while achieving the same technical effect
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 enhances the structural stability and manufacturing ease of high-frequency mode generators, improving accuracy and reducing undesired reflections, while maintaining a low profile and flexibility in design.
Implementation Method 1
The lens has a bottom surface facing the tank, which is adapted to transmit electromagnetic waves having said second propagation mode and to reflect electromagnetic waves having said first propagation mode
Implementation Method 2
an upper surface opposite the bottom surface which is adapted to reflect electromagnetic waves and to turn a field of said electromagnetic waves upon reflection, so as to change a propagation mode of said electromagnetic waves from one of said first and second propagation modes to another
Implementation Method 3
The lens has a bottom surface facing the tank, which is adapted to transmit electromagnetic waves having said second propagation mode
Data Source
Figure 1
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Figure 3~4
AI summary
A radar level gauging system for determining at least one process variable related to a distance to a surface of a product in a tank comprising transceiver circuitry,processing circuitry, a wave guiding structure arranged guide measurement signals towards the surface, and a radiator connected to the transceiver circuitry and arranged to emit the measurement signal into the wave guiding structure. The system further comprises a mode generator adapted to convert electromagnetic waves emitted from the radiator from a first propagation mode to a second propagation mode, wherein the mode generator includes a lens in the form of a body transparent to electromagnetic waves in the operating frequency range. With this design, electromagnetic waves having the first propagation mode emitted by the radiator into the lens will be reflected at least twice within the lens (first in the bottom surface and then in the upper surface). At the second reflection (in the upper surface of the lens), the propagation mode will be changed, and the electromagnetic waves exiting the lens will have the second propagation mode.