Lateral Bulk Acoustic Wave Resonator With Acoustic Mirror Cooling
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Solution Overview
Problem
Existing laterally excited bulk acoustic wave resonators face challenges with heat dissipation and mechanical ruggedness, particularly in high-frequency applications, which can lead to power durability issues and acoustic energy leakage.
Innovation Solution
A laterally excited bulk acoustic wave device is designed with a solid acoustic mirror and a support substrate of high thermal conductivity, where the piezoelectric layer is bonded to the substrate, and an interdigital transducer electrode is used to excite bulk acoustic waves, effectively confining acoustic energy and enhancing heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a laterally excited bulk acoustic wave resonator is used for high-frequency applications, then the resonant frequency is improved, but heat dissipation deteriorates leading to power durability issues
Solution Approach 1:
A heat sink is introduced as an intermediary component between the piezoelectric layer and the external environment. The heat sink receives heat from the piezoelectric layer through thermal conduction and dissipates it to the surroundings, serving as a mediator that separates the heat generation source from the operational components, thereby improving power durability in high-frequency applications
2Speed
If a laterally excited bulk acoustic wave resonator is used, then high-frequency resonance is achieved, but acoustic energy leakage increases reducing reliability
Solution Approach 1:
The piezoelectric layer is extracted and bonded to a separate support substrate. This separation allows the piezoelectric layer to be optimized for high-frequency resonance while the support substrate provides mechanical stability and acoustic energy confinement, preventing leakage and improving reliability
3Strength
If the piezoelectric layer is bonded to the substrate, then mechanical ruggedness is improved, but acoustic energy may leak into the substrate
Solution Approach 1:
A heat sink is positioned between the piezoelectric layer and the substrate. This heat sink acts as an intermediary that provides thermal management while also serving as an acoustic barrier, preventing acoustic energy from leaking into the substrate while maintaining mechanical ruggedness through the bonded 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
This configuration improves mechanical ruggedness and thermal dissipation, allowing for high-frequency resonance with increased power durability and reduced acoustic energy leakage, making it suitable for applications like 5G NR and 4G LTE frequency bands.
Implementation Method 1
a solid acoustic mirror on the support substrate, a piezoelectric layer on the solid acoustic mirror... The solid acoustic mirror is arranged to confine acoustic energy such that the support substrate is free from acoustic energy during operation
Implementation Method 2
the support substrate is arranged to increase heat dissipation of the laterally excited bulk acoustic wave device... heat associated with the bulk acoustic wave is arranged to flow through the solid acoustic mirror to the support substrate... the support substrate has a thermal conductivity that is higher than a thermal conductivity of the piezoelectric layer
Implementation Method 3
an interdigital transducer electrode on the piezoelectric layer. The interdigital transducer electrode is arranged to laterally excite a bulk acoustic wave
Data Source
AI summary
A laterally excited bulk acoustic wave device is disclosed. The laterally excited bulk acoustic wave device can include a support substrate, a solid acoustic mirror on the support substrate, a piezoelectric layer on the solid acoustic mirror, and an interdigital transducer electrode on the piezoelectric layer. The interdigital transducer electrode is arranged to laterally excite a bulk acoustic wave.