Acoustic Wave Filter Layout With Obstacles Between Feedback Channels
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Solution Overview
Problem
Acoustic wave filters face challenges in achieving high rejection performance across multiple frequency bands due to acoustic coupling between interdigital transducers (IDTs) of different feedback circuits, which degrades rejection performance and limits design flexibility in physical layout.
Innovation Solution
Incorporating an acoustic obstacle made of the same material as the IDTs, such as a polymer, between the IDTs of different feedback circuits to reduce or eliminate acoustic coupling, allowing for improved rejection performance and design flexibility by absorbing or scattering acoustic energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple feedback circuits are integrated in close proximity to achieve compact layout, then device area is reduced, but acoustic coupling between IDTs of different feedback circuits increases causing degraded rejection performance
Solution Approach 1:
An acoustic obstacle is introduced as an intermediary element between IDTs of different feedback circuits. This obstacle acts as a mediator that blocks acoustic energy propagation from one IDT to another, preventing harmful acoustic coupling while allowing the feedback circuits to be positioned in close proximity for compact device layout.
Solution Approach 2:
The acoustic obstacle is extracted as a separate functional element from the IDT structures themselves. By removing the acoustic coupling path through the substrate and replacing it with a dedicated acoustic barrier, the design enables compact integration without sacrificing rejection performance.
2Reliability
If acoustic obstacle is introduced to reduce acoustic coupling between feedback circuits, then rejection performance is improved, but device complexity increases
Solution Approach 1:
The acoustic obstacle is implemented with localized properties - it is positioned only where acoustic coupling occurs between specific IDTs, and its material composition is tailored to provide acoustic blocking in those specific regions. This localized approach provides the necessary rejection performance without unnecessarily complicating the entire device structure.
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 acoustic obstacle effectively reduces unwanted frequency responses, enhancing rejection performance across multiple frequency bands and enabling more flexible physical layouts for acoustic wave devices.
Implementation Method 1
Incorporating an acoustic obstacle made of the same material as the IDTs, such as a polymer, between the IDTs of different feedback circuits to reduce or eliminate acoustic coupling, allowing for improved rejection performance and design flexibility by absorbing or scattering acoustic energy.
Implementation Method 2
Incorporating an acoustic obstacle made of the same material as the IDTs, such as a polymer, between the IDTs of different feedback circuits to reduce or eliminate acoustic coupling, allowing for improved rejection performance and design flexibility by absorbing or scattering acoustic energy.
Data Source
AI summary
Aspects of this disclosure relate to an acoustic wave device that includes an acoustic obstacle disposed between canceling circuits coupled to one or more acoustic wave filters. The canceling circuits can cancel frequency components within different frequency bands. The acoustic obstacle can reduce acoustic coupling between the canceling circuits by scattering and/or absorbing acoustic energy.