Acoustic Wave Module Shielding Layout for Better Isolation
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Solution Overview
Problem
Simply providing a metal layer connected to the ground between acoustic wave elements in an acoustic wave device is insufficient to achieve effective electromagnetic shielding, leading to deterioration in device characteristics.
Innovation Solution
The acoustic wave device incorporates a first substrate with a first acoustic wave element, a second substrate with a second acoustic wave element, a ground terminal, a first metal layer between the acoustic wave elements in an air gap, and a second metal layer covering half or more of the side surfaces of the first substrate, electrically connecting the first metal layer to the ground terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a metal layer is provided between the first acoustic wave element and the second acoustic wave element, then electromagnetic shielding is provided, but the shielding effect is insufficient and characteristics deteriorate
Solution Approach 1:
The patent extends the metal layer from a simple planar configuration to a three-dimensional structure that covers side surfaces of the substrate. This dimensional extension creates a more comprehensive shielding barrier that blocks electromagnetic fields from multiple directions, not just from the top surface, thereby achieving effective shielding while maintaining device characteristics.
Solution Approach 2:
The metal layer is configured to wrap around and enclose the acoustic wave elements, creating a nested shielding structure. The metal layer is provided on the front surface, rear surface, and side surfaces, forming a multi-layered protective enclosure that effectively isolates the acoustic wave elements from external electromagnetic interference.
2Object-affected harmful factors
If the metal layer is extended to cover side surfaces, then electromagnetic shielding is improved, but device complexity increases
Solution Approach 1:
The metal layer serves multiple functions simultaneously: it provides electromagnetic shielding on the front surface, rear surface, and side surfaces, while also acting as a ground reference and structural element. This multi-functionality allows comprehensive shielding without proportionally increasing device complexity, as a single component achieves multiple protective roles.
Solution Approach 2:
The patent integrates the shielding function with the substrate structure by providing the metal layer as part of the substrate assembly. The metal layer is formed on multiple surfaces and connected to a ground terminal, merging the shielding structure with the overall device architecture rather than adding it as a separate, complex subsystem.
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 configuration enhances the electromagnetic shielding effect, improving the isolation characteristics of the acoustic wave device by effectively grounding the shield metal layer, which reduces electromagnetic field coupling and maintains device performance.
Implementation Method 1
a second metal layer that covers half or more of a total area of the side surfaces of the first substrate and electrically connects the first metal layer and the ground terminal
Data Source
AI summary
An acoustic wave device includes a first substrate having first and second surfaces opposite from each other, and side surfaces connecting the first and second surfaces, a first acoustic wave element disposed on the first surface of the first substrate, a second substrate that is provided over the first surface of the first substrate and over the first acoustic wave element and has a first air gap between the second and first substrates, a second acoustic wave element disposed on the second substrate, a ground terminal disposed on the second surface of the first substrate, a first metal layer provided between the first and second acoustic wave elements and located in the first air gap, and a second metal layer that covers half or more of a total area of the side surfaces of the first substrate and electrically connects the first metal layer and the ground terminal.