Multilayer Waveguide Interface Layout for Low-Leakage RF Antennas
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Solution Overview
Problem
Multilayer waveguide structures for radiofrequency antennas face issues such as leakage losses due to adhesive materials, mechanical failures from blind metal vias, and complexity in corporate feed networks, leading to bulky and costly antenna designs.
Innovation Solution
A multilayer waveguide structure with patterned interface layers and metal vias or trenches, where the adhesive layer is locally thinner to prevent direct electric contact and additional metal thickness is added, reducing leakage losses and simplifying manufacturing by reducing the number of layers and vias.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive material is used to connect substrate layers in multilayer stack, then substrates are joined together, but leakage losses increase due to adhesive material
Solution Approach 1:
The adhesive layer thickness is varied locally across the interface layer. In regions away from metal vias/trenches, the adhesive layer is thinner to reduce leakage losses. Near metal vias/trenches, the adhesive layer is thicker to prevent direct electric contact between metal layers while still providing adequate mechanical bonding. This local variation in adhesive thickness resolves the contradiction between maintaining strong substrate connection and minimizing leakage losses.
2Reliability
If blind metal vias and buried metal vias are drilled through substrates, then electrical connections are established, but mechanical failure occurs and manufacturing complexity increases
Solution Approach 1:
The invention extracts the problematic blind and buried vias from the design by using through-vias that extend completely through the substrate layers. This eliminates the need for complex drilling and filling operations required for blind/buried vias, while still providing reliable electrical connections. The through-vias are simpler to manufacture and reduce the risk of mechanical failure associated with incomplete via formation.
Solution Approach 2:
The adhesive layer serves as an intermediary between metal layers in through-vias. By carefully controlling adhesive thickness (thinner away from vias, thicker near vias), the adhesive mediates between the need for electrical connectivity and the need to prevent leakage, while also providing mechanical support to prevent via failure.
3Adaptability or versatility
If number of layers is increased to bring input signal from feeding waveguide toward radiating surface, then wide band operation is achieved, but antenna structure becomes bulky and manufacturing cost increases
Solution Approach 1:
The invention changes the parameter of adhesive layer thickness to optimize performance. By making the adhesive layer thinner in most regions (while maintaining adequate thickness near vias), the overall antenna thickness is reduced. This parameter change allows wide band operation to be achieved with fewer layers or thinner layers, thereby reducing the bulky structure problem while maintaining electrical 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
The solution reduces leakage losses, simplifies manufacturing, and decreases the overall thickness and cost of the antenna, while maintaining wide band operation and agility, resulting in a more efficient and cost-effective radiofrequency antenna design.
Implementation Method 1
multilayer waveguide structures for radiofrequency antennas
Data Source
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AI summary
A multilayer waveguide structure (2) for a radiofrequency antenna comprises: - a stack of substrates (4) separated by each other by interface layers (10), the substrates having a permittivity larger or equal to 1, and - metal vias (12) or metal trenches formed in at least some of the substrates. Each interface layer (10) comprises a first metal layer (16), a second metal layer (18), and an adhesive layer (14) between the first metal layer (16) and the second metal layer (18). At least one of said interface layer (10) comprises patterned structures (R12), for which the adhesive layer (14) is thinner while still preventing a direct electric contact between the first and second metal layers (16, 18), and each said patterned structure (R12) is located near or at the base or the top of a metal via (12) or metal trench.