Stacked Acoustic Wave Filter Shielding for TDD Signal Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In radio frequency modules using two acoustic wave devices as filters, significant interference occurs between transmission and reception signals due to differences in signal strength, making it difficult to improve isolation between the filters, especially during asynchronous communication in TDD scenarios.
Innovation Solution
A radio frequency module design that includes a mounting board with a first and second acoustic wave filter, where the filters support different communication bands and are separated by a hollow space with a shield electrode, enhancing electromagnetic shielding and improving isolation between the filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two acoustic wave devices are used as acoustic wave filters, then filter functionality is provided, but interference occurs between transmission and reception signals due to large signal strength differences
Solution Approach 1:
A shield electrode is introduced as an intermediary element between the first and second acoustic wave filters. This shield electrode acts as a mediator that blocks electromagnetic interference between the transmission path (first filter) and reception path (second filter), thereby resolving the signal interference problem while maintaining filter functionality
Solution Approach 2:
The internal structure of the acoustic wave filter component is segmented into distinct functional regions using the shield electrode. This segmentation separates the transmission signal path from the reception signal path within the same component, preventing signal leakage and interference between the two paths
2Volume of moving object
If acoustic wave filters are placed close together, then device size is reduced, but isolation between filters deteriorates
Solution Approach 1:
The shield electrode extends in the thickness direction (vertical dimension) of the mounting board, creating a three-dimensional shielding structure. This dimensional approach allows close horizontal placement of filters while maintaining isolation through vertical shielding, effectively resolving the size-isolation trade-off
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 improves signal isolation between the first and second acoustic wave filters, enabling efficient asynchronous communication in TDD by reducing noise resistance and heat dissipation issues, thus enhancing signal quality and module performance.
Implementation Method 1
The first shield electrode is located in the hollow space and covers at least one of the first functional electrode or the second functional electrode
Data Source
AI summary
A radio frequency module including a mounting board, a first acoustic wave filter, a second acoustic wave filter, and a shield electrode. The second acoustic wave filter is disposed on the first acoustic wave filter. The first acoustic wave filter supports a first communication band, and the second acoustic wave filter supports a second communication band. The first acoustic wave filter includes a first support member and a first functional electrode. The second acoustic wave filter includes a second support member and a second functional electrode. The first functional electrode and the second functional electrode are located in a hollow space formed between the first support member and the second support member in a thickness direction of the mounting board, and face each other. The shield electrode is located in the hollow space and covers at least one of the first functional electrode and the second functional electrode.