Dual-Substrate Acoustic Multiplexer for Heat and Isolation
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Solution Overview
Problem
Existing multiplexer designs face challenges in achieving both improved reliability in power durability and suppression of deterioration in isolation characteristics.
Innovation Solution
A multiplexer design with acoustic wave resonators on opposing substrates, where resonators are strategically positioned and divided between two substrates to minimize electromagnetic field coupling and enhance heat dissipation, utilizing a shield layer and specific resonator placements to inhibit signal leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all acoustic wave resonators are mounted on a single substrate, then the device structure is simple, but heat dissipation is insufficient and reliability in power durability deteriorates
Solution Approach 1:
The acoustic wave resonators are divided into two groups: first acoustic wave resonators mounted on a first substrate and second acoustic wave resonators mounted on a second substrate. This segmentation distributes heat generation across multiple substrates, improving heat dissipation and reliability in power durability while maintaining a relatively simple overall device structure.
2Reliability
If acoustic wave resonators are divided and mounted on opposing substrates, then heat dissipation is enhanced, but electromagnetic field coupling increases and isolation characteristics deteriorate
Solution Approach 1:
The electrode fingers of the interdigital transducers on the first and second substrates are configured with asymmetric orientations - the first electrode fingers are not parallel to the second electrode fingers. This asymmetric configuration reduces electromagnetic field coupling between the opposing substrates, improving isolation characteristics while maintaining the heat dissipation benefits of the divided substrate structure.
3Object-affected harmful factors
If electrode fingers are made non-parallel, then isolation characteristics are improved, but manufacturing precision requirements increase
Solution Approach 1:
Instead of adjusting the in-plane orientation of electrode fingers, the invention introduces a vertical dimension by mounting resonators on opposing substrates with different orientations. The first interdigital transducer and second interdigital transducer are configured with different orientations in three-dimensional space, achieving isolation improvement through spatial separation rather than precise in-plane alignment.
4Volume of moving object
If device size is reduced through miniaturization, then integration is improved, but heat dissipation capacity decreases
Solution Approach 1:
The invention employs a nested dual-substrate configuration where first acoustic wave resonators and second acoustic wave resonators are mounted on opposing substrates that face each other with an air gap. This nested arrangement allows heat dissipation surfaces to be distributed in three-dimensional space rather than confined to a single plane, enabling effective heat dissipation within a compact device volume.
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 inhibits signal leakage, improves isolation characteristics, and enhances reliability in power durability while allowing for miniaturization.
Implementation Method 1
a first acoustic wave resonator and a second acoustic wave resonator, each other being different from the first acoustic wave resonator
Data Source
AI summary
A multiplexer includes a transmit filter including first acoustic wave resonators connected to a first path between a common terminal and a transmit terminal, one or some first acoustic wave resonators of the first acoustic wave resonators being provided on a first substrate, and a remaining first acoustic wave resonator being provided on a second substrate, and a receive filter including second acoustic wave resonators connected to a second path between the common terminal and a receive terminal, one or some second acoustic wave resonators of the second acoustic wave resonators being provided on the first substrate and a remaining second acoustic wave resonator being provided on the second substrate, and a resonator closest to the receive terminal in a plan view among the one or some first and second acoustic wave resonators being a second acoustic wave resonator of the one or some second acoustic wave resonators.