SAW Filter Cover Shielding in Compact High-Frequency Modules
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing high-frequency modules face challenges in reducing size while minimizing mutual interference between surface acoustic wave filters and internal wiring patterns, leading to increased area requirements on the multilayer substrate.
Innovation Solution
The proposed high-frequency module design includes a shield electrode positioned between the surface acoustic wave filter and internal wiring pattern, with a cover and piezoelectric substrate arrangement that reduces interference, allowing for a smaller module size without the need for additional shielding on the substrate. This configuration also includes a resin member for enhanced coupling between the electrode and wiring patterns, improving attenuation characteristics outside the pass band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shield electrode is disposed on the multilayer substrate to prevent mutual interference between the surface acoustic wave filter and internal wiring pattern, then interference is reduced, but the area required for electrode patterns increases
Solution Approach 1:
The shield electrode is moved from the horizontal plane (on the multilayer substrate) to the vertical dimension (on the cover facing the piezoelectric substrate). This spatial repositioning maintains the shielding function while eliminating the need for additional area on the substrate, as the shield electrode now utilizes the vertical space above the filter assembly.
Solution Approach 2:
The cover serves as an intermediary structure that carries the shield electrode. Instead of placing the shield electrode directly on the substrate or requiring substrate modifications, the cover acts as a mounting platform for the shield electrode, allowing it to be positioned optimally for interference reduction without consuming substrate area.
2Volume of moving object
If the module size is reduced, then integration is improved, but mutual interference between surface acoustic wave filter and peripheral wiring pattern increases
Solution Approach 1:
By positioning the shield electrode on the cover in the vertical dimension rather than on the substrate plane, the design achieves effective interference shielding without increasing the horizontal footprint of the module. This allows the module to maintain a compact size while still providing adequate shielding against mutual interference.
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 effectively reduces module size while preventing undesirable interference and enhancing attenuation characteristics outside the pass band, ensuring stronger coupling with a smaller footprint.
Implementation Method 1
a surface acoustic wave filter that includes a piezoelectric substrate, an electrode pattern that is provided on the piezoelectric substrate
Implementation Method 2
a shield electrode that is grounded is provided in or on a surface of the cover that faces the module substrate or is provided in or on a surface of the cover that faces the piezoelectric substrate
Data Source
AI summary
A high-frequency module includes a module substrate including an internal wiring pattern, and a SAW filter including a piezoelectric substrate, an electrode pattern on the piezoelectric substrate, a support surrounding the electrode pattern, and a cover on the support covering the electrode pattern to define a hollow space together with the support and the piezoelectric substrate. The module substrate, the cover, and the piezoelectric substrate are disposed in this order in a perpendicular or substantially perpendicular direction with respect to the module substrate, and a shield electrode is provided on a surface of the cover that faces the module substrate or on a surface of the cover that faces the piezoelectric substrate.