Acoustic Wave Multiplexer Shield Layout for Filter Isolation
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Solution Overview
Problem
Existing multiplexers face challenges in achieving high isolation between filter devices while maintaining a compact size, as traditional designs with full-shield peripheries increase device size and complexity.
Innovation Solution
The proposed multiplexer design incorporates a shield wire between the inductor and acoustic wave resonators to reduce electromagnetic field coupling, improving isolation between filter devices and minimizing the overall size by eliminating the need for a full-shield circumference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shield is formed around the entire periphery of the filter device, then isolation with other filter devices is increased, but the sizes of the filter device and the multiplexer are increased
Solution Approach 1:
The patent divides the shielding function into segments by placing individual shield wires between specific adjacent filter devices rather than implementing a continuous shield around each filter device. This segmentation approach maintains the isolation function while significantly reducing the total shielding material and overall device size.
Solution Approach 2:
The patent applies shielding only where necessary - specifically between adjacent filter devices that require isolation - rather than providing uniform shielding around the entire periphery of each filter device. This local quality approach optimizes the balance between isolation performance and device compactness.
2Reliability
If shield wires are added between filter devices, then isolation is improved, but device complexity increases
Solution Approach 1:
The patent merges the shield wire structure with the existing substrate and filter device layout, integrating the shielding function into the overall device architecture rather than adding it as a separate complex subsystem. This merging approach maintains isolation performance while minimizing increases in device complexity.
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 design significantly enhances isolation in the pass band of the second filter device while reducing the multiplexer's size, achieving improved performance and compactness compared to traditional designs.
Implementation Method 1
the electromagnetic field coupling between the inductor and the acoustic wave resonator is able to be significantly reduced or prevented
Data Source
AI summary
A multiplexer includes a common terminal, a first terminal, a second terminal, a first filter device including acoustic wave resonators including series resonators and parallel resonators, an inductor provided between an acoustic wave resonator and the first terminal, and a second filter device. The first filter device further includes a first ground terminal to which a parallel resonator is electrically connected, a second ground terminal to which the parallel resonators are electrically connected, and a wiring provided between the inductor and an acoustic wave resonator. In the first filter device, the wiring is electrically connected to the first ground terminal, and the first ground terminal is not connected to the second ground terminal.