Electro-Acoustic Transducer Subtracks for Acoustic Coupling Cancellation
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Solution Overview
Problem
High integration density in electro-acoustic transducers leads to mutual interaction and unwanted acoustic coupling between closely arranged transducers, deteriorating electrical properties and signal quality in RF-filter components.
Innovation Solution
The electro-acoustic transducer design incorporates a plurality of subtracks with segments of electrode fingers shifted by half the acoustic wavelength, creating a 180° phase shift to achieve destructive interference and reduce unwanted acoustic coupling, while maintaining improved RF-filter performance through a wave guiding structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If transducers are arranged closely to increase integration density, then spatial dimensions are minimized, but unwanted acoustic coupling between transducers occurs
Solution Approach 1:
The patent converts the harmful radiated acoustic waves into a beneficial effect by using destructive interference. Subtracks are designed with shifted electrode finger segments (λ/2 shift) that generate acoustic waves 180° out of phase, causing these waves to cancel each other out and eliminate unwanted acoustic coupling between adjacent transducers
Solution Approach 2:
The transducer is segmented into multiple subtracks, where each subtrack contains segments of electrode fingers. This segmentation allows different subtracks to generate acoustic waves with specific phase relationships, enabling destructive interference to cancel unwanted radiation while maintaining the desired acoustic wave generation for filter operation
2Volume of moving object
If transducers are arranged closely to increase integration density, then device size is reduced, but electrical properties and signal quality deteriorate
Solution Approach 1:
The patent converts the harmful acoustic coupling into a beneficial cancellation effect through destructive interference. By designing subtracks with λ/2 shifted electrode segments, the radiated acoustic waves from different subtracks are made 180° out of phase, causing them to cancel each other out and prevent deterioration of electrical properties and signal quality in adjacent transducers
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 effectively minimizes unwanted acoustic coupling and maintains or improves RF-filter performance by achieving destructive interference between adjacent transducers, reducing insertion loss and enhancing signal quality, particularly in rejection bands.
Implementation Method 1
BAW radiated from a first transducer may be reflected at the bottom surface of a piezoelectric substrate
Implementation Method 2
BAW radiated from a first transducer may be reflected at the bottom surface of a piezoelectric substrate
Implementation Method 3
an essentially destructive interference is obtained and an unwanted acoustic coupling between adjacent transducers is eliminated or at least strongly reduced
Data Source
AI summary
An electro-acoustic transducer and an electro-acoustic component including an electro-acoustic transducer are disclosed. In an embodiment the transducer includes a first and a second bus bar, a plurality of electrode fingers and a plurality of two or more sub tracks, wherein each electrode finger is electrically connected to one of the bus bars, wherein each sub track extends along a longitudinal direction, wherein all sub tracks are arranged one next to another in a transversal direction, wherein at least a first of the sub tracks includes segments of the electrode fingers and has an associated sub track with segments of the electrode fingers, wherein the segments of the electrode fingers of the first sub track are shifted by a distance S=.lamda./2 along the longitudinal direction relative to the segments of the electrode fingers of the associated sub track, and wherein .lamda. is an acoustic wavelength.