Ridge Gap Waveguides for High Frequency Signal Transmission
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Solution Overview
Problem
Existing transmission lines and waveguides, such as coaxial lines and microstrip lines, experience high ohmic losses and manufacturing challenges at frequencies above 30 GHz, making them unsuitable for high-frequency applications.
Innovation Solution
The development of ridge gap waveguides and gap transmission lines, where a narrow gap between two parallel conducting surfaces with specific textures or structures controls wave propagation, preventing unwanted modes and reducing losses by confining fields within the gap, allowing for efficient high-frequency signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional transmission lines (coaxial, microstrip) are used at frequencies above 30 GHz, then existing manufacturing techniques can be applied, but ohmic losses increase significantly
Solution Approach 1:
The waveguide structure is segmented into modular components (elbows, bends, transitions, connectors) that can be manufactured separately and assembled. This segmentation allows each component to be optimized for low loss while maintaining manufacturability through standard fabrication processes.
Solution Approach 2:
The invention transitions from planar microstrip transmission lines to three-dimensional waveguide structures. By utilizing the third dimension (vertical gap between plates), the design achieves lower ohmic losses through reduced current density while maintaining compact form factors through careful dimensional optimization.
2Reliability
If hollow waveguides are made thinner to work at higher frequencies, then single mode operation is achieved, but manufacturing difficulty increases
Solution Approach 1:
The waveguide employs composite construction with parallel conducting plates separated by dielectric spacers or air gaps. This composite structure achieves the required electrical dimensions for single-mode operation while using standard manufacturing tolerances for each component, avoiding the need for precision-machined thin-walled hollow waveguides.
Solution Approach 2:
Dielectric spacers or air gaps serve as intermediaries between the parallel conducting plates, maintaining the precise gap dimension required for single-mode operation without requiring the plates themselves to be precision-machined to tight tolerances. This intermediary approach decouples the electrical performance requirements from mechanical manufacturing constraints.
3Ease of manufacture
If microstrip lines are used at high frequencies, then substrate integration is achieved, but losses increase due to substrate effects
Solution Approach 1:
The invention extracts the electromagnetic field confinement from the lossy substrate by creating an air-filled or dielectric-spacer-filled gap between parallel plates. The field primarily resides in the low-loss air or dielectric region rather than in the lossy substrate, dramatically reducing ohmic losses while maintaining integration capability through PCB-mounted plate structures.
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 solution effectively reduces ohmic losses and manufacturing complexities, enabling reliable high-frequency transmission lines and waveguides with lower losses and improved manufacturability, suitable for frequencies above 30 GHz.
Implementation Method 1
a narrow gap between two parallel conducting surfaces with specific textures or structures controls wave propagation, preventing unwanted modes and reducing losses by confining fields within the gap
Implementation Method 2
At least one of the surfaces is provided with means to prohibit the waves from propagating in other directions between them than along the ridge, e.g. by using a texture or structure in the metal surface itself
Data Source
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AI summary
A new way of realizing microwave devices, such as electromagnetic transmission lines, waveguides and circuits of them, is disclosed, that is advantageous when the frequency is so high that existing transmission lines and waveguides have too large losses or cannot be manufactured cost-effectively with the tolerances required. Thus, the new technology is intended to replace coaxial lines, hollow cylindrical waveguides, and microstrip lines and other substrate-bound transmission lines at high frequencies. The microwave devices are realized by a narrow gap between two parallel surfaces of conducting material, by using a texture or multilayer structure on one of the surfaces. The fields are mainly present inside the gap, and not in the texture or layer structure itself, so the losses are small. The microwave device further comprises one or more conducting elements, such as a metal ridge or a groove in one of the two surfaces, or a metal strip located in a multilayer structure between the two surfaces. The waves propagate along the conducting elements. No metal connections between the two metal surfaces are needed. At least one of the surfaces is provided with means to prohibit the waves from propagating in other directions between them than along the ridge, groove or strip. At very high frequency the gap waveguides and gap lines may be realized inside an IC package or inside the chip itself.