SMR Electromagnetic Shielding Wall for Signal Isolation
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Solution Overview
Problem
Conventional solidly mounted resonators lack electromagnetic shielding, leading to reduced performance and quality factors due to poor C-axis preferred orientation of electrode layers, and require additional shielding devices, which increase dimension and reduce performance.
Innovation Solution
A solidly mounted resonator with an integrated electromagnetic shielding structure, featuring a substrate with a metal shielding wall surrounding the acoustic-wave reflecting and resonance function layers, and a method for manufacturing this resonator that includes forming multiple metal rings and dielectric reflection layers in an interleaved manner to provide effective shielding without additional devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional SMR devices are used without electromagnetic shielding, then the device dimension remains small, but electromagnetic interference from external and internal sources degrades performance and quality factor
Solution Approach 1:
The patent combines the electromagnetic shielding function with the acoustic wave reflecting layer by integrating a metal shielding wall into the existing SMR structure. The shielding wall is formed simultaneously with the acoustic wave reflecting layer during fabrication, merging two previously separate functions (acoustic reflection and EM shielding) into a single integrated structure, thereby providing protection against electromagnetic interference without requiring additional separate shielding devices
Solution Approach 2:
The metal shielding wall serves multiple functions: it acts as an acoustic wave reflecting layer to confine acoustic energy within the resonator, and simultaneously provides electromagnetic shielding to protect against external and internal EM interference. This multi-functional design eliminates the need for separate shielding components while maintaining small device dimensions
2Object-affected harmful factors
If additional electromagnetic shielding devices are added to conventional SMR, then electromagnetic shielding is provided, but device dimension increases and performance is reduced
Solution Approach 1:
The patent merges the electromagnetic shielding function with the acoustic wave reflecting layer by integrating a metal shielding wall into the existing SMR structure. The shielding wall is formed simultaneously with the acoustic wave reflecting layer during fabrication, merging two previously separate functions (acoustic reflection and EM shielding) into a single integrated structure, thereby providing protection against electromagnetic interference without requiring additional separate shielding devices
Solution Approach 2:
The metal shielding wall serves multiple functions: it acts as an acoustic wave reflecting layer to confine acoustic energy within the resonator, and simultaneously provides electromagnetic shielding to protect against external and internal EM interference. This multi-functional design eliminates the need for separate shielding components while maintaining small device dimensions
3Reliability
If conventional SMR fabrication process is used, then manufacturing is simple, but the upper electrode, piezoelectric layer, and lower electrode do not have good C-axis preferred orientation, reducing performance
Solution Approach 1:
The patent introduces a seed layer fabrication step before forming the piezoelectric layer to pre-establish the crystal orientation foundation. By preparing the seed layer with appropriate crystal structure and orientation in advance, the subsequent piezoelectric layer growth automatically inherits and maintains good C-axis preferred orientation, eliminating the need for post-fabrication orientation correction while keeping the process straightforward
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 electromagnetic shielding, reduces noise interference, and improves heat dissipation, maintaining high performance and small dimensions while ensuring effective signal isolation and product yield.
Implementation Method 1
The resonance function layer is configured to implement conversion between electrical energy and mechanical energy via the piezoelectric layer, and the mechanical energy is in a form of acoustic waves
Implementation Method 2
The acoustic-wave reflecting layer is characterized by having alternating high and low acoustic impedance, and thus is capable to reflect the acoustic waves effectively
Implementation Method 3
the metal shielding wall surrounds an effective region in the acoustic-wave reflecting layer and the lower electrode when viewed along a direction perpendicular to the substrate
Data Source
Figure 1~2
Figure 3
Figure 4~5a
AI summary
A solidly mounted resonator having an electromagnetic shielding structure, and a manufacturing process. The resonator comprises: a substrate (101); an acoustic wave reflecting layer (201) formed on the substrate (101); and a resonating functional layer (301) formed on the acoustic wave reflecting layer (201). The resonator further comprises a metal shielding wall (401) formed on the substrate (101), and the metal shielding wall (401) forms an encirclement on the periphery of effective regions (1-1) of the acoustic wave reflecting layer (201) and the resonating functional layer (301). Moreover, by forming a closed electromagnetic shielding layer on the periphery of effective regions (1-1) of the acoustic wave reflecting layer (201) and the resonating functional layer (301), the electromagnetic shielding layer is fabricated while the resonator is being fabricated, thus making it unnecessary to add an electromagnetic shielding device, preventing the resonator from being affected by external and internal electromagnetic interference sources while ensuring a small volume and high performance, and greatly enhancing signal isolation of a radio frequency terminal product and reducing noise signals particularly for adjacent frequency bands and signal transmitting ends.