Air-Cavity Waveguide Structure for Low-Loss High-Frequency Signals
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Solution Overview
Problem
Existing substrate integrated waveguide (SIW) structures suffer from energy loss during signal transmission, particularly at higher frequencies, due to the use of dielectric materials, which limits the selection of materials and increases implementation costs.
Innovation Solution
The waveguide structure incorporates an air cavity defined by the conductor connection layer and parts of the circuit layers, reducing energy loss during signal transmission, enhancing high average power handling, and isolating signal transmission characteristics from external dielectric materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If dielectric material is used in substrate integrated waveguide structure, then structural support and insulation are provided, but energy loss increases during signal transmission
Solution Approach 1:
The patent extracts the dielectric material from the signal transmission path by creating an air cavity (void space) within the multilayer circuit board structure. The air cavity is formed by removing material from the interior of the circuit board, allowing signals to propagate through air rather than dielectric material, thereby reducing energy loss while maintaining the overall structural integrity provided by the circuit board layers.
2Reliability
If dielectric material is used in waveguide structure, then structural integrity is maintained, but signal transmission characteristics are affected at high frequencies
Solution Approach 1:
The patent applies local quality by creating a specific air cavity region within the circuit board where signal transmission occurs, while the surrounding areas maintain the dielectric structure for support. The air cavity is precisely positioned and dimensioned to optimize signal propagation characteristics at high frequencies, while the outer circuit board structure provides mechanical support and insulation.
3Loss of energy
If copper pillar is used to connect metal surfaces, then electrical connection is established, but energy loss increases and manufacturing complexity increases
Solution Approach 1:
The patent merges the functions of electrical connection and structural support by using the circuit board trace layers and conductor connection layers that are already part of the multilayer construction. Instead of adding separate copper pillars, the conductive paths are formed by extending the existing circuit traces through the layers, connecting the metal surfaces on opposite sides of the air cavity through the conductor connection layer.
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 design achieves low energy losses, high average power handling, and independence from external dielectric materials, making it suitable for high-frequency applications such as wireless communication, automotive radar, and satellite communication.
Implementation Method 1
At present, substrate integrated waveguide (SIW) structures are used in high-frequency circuits most of the time... the dielectric material covered by the upper and lower metal surfaces and the copper pillar may lead to energy loss during signal transmission. Particularly, when the frequency increases, such loss increases.
Data Source
Figure 1A~1B
Figure 1C
Figure 2
AI summary
A waveguide structure includes a dielectric layer, a plurality of circuit layers, a plurality of insulation layers, and a conductor connection layer. The dielectric layer has an opening. The circuit layers are disposed on the dielectric layer. The insulation layers and the circuit layers are alternately stacked. The conductor connection layer covers an outer wall of the opening in a direction perpendicular to the circuit layers and connects at least two circuit layers on two opposite sides of the opening. At least the conductor connection layer and a part of the circuit layers define an air cavity for transmitting signals at a position corresponding to the opening.