Acoustic Resonator Filter Layout for Heat Dissipation and Wide Bandwidth
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Solution Overview
Problem
There is a need for small and lightweight filters and resonant elements in modern mobile devices that offer excellent performance and heat dissipation characteristics, which existing technologies such as dielectric filters and metal cavity filters do not adequately provide.
Innovation Solution
An acoustic resonator filter is designed with a combination of film bulk acoustic resonators (FBARs) and solidly mounted resonators (SMRs), where the SMRs have excellent heat dissipation characteristics and FBARs provide high implementation efficiency and filtration characteristics, with a structure that includes an insulating layer, substrate, and sacrificial layers to enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If acoustic resonators are used to achieve small size and good performance, then filter size is reduced and performance is improved, but heat dissipation becomes insufficient
Solution Approach 1:
The filter is divided into multiple resonator units (series resonators and shunt resonators) that are spatially segmented and electrically connected. This segmentation allows heat to be distributed across multiple discrete components rather than concentrated in a single element, improving overall heat dissipation while maintaining compact filter size.
Solution Approach 2:
Different regions of the filter are designed with different thermal characteristics. The substrate and support structures provide localized heat sinking, while the resonator elements are positioned to optimize both acoustic performance and thermal management. This local differentiation of thermal properties enables effective heat dissipation within the compact structure.
2Reliability
If more resonator elements are added to improve filtration characteristics, then filter performance is enhanced, but device complexity increases
Solution Approach 1:
Multiple resonator elements are merged into a single integrated filter structure where series resonators and shunt resonators work together in a coordinated manner. The electrical connections between resonators are designed to combine their individual filtration characteristics into a unified frequency response, achieving enhanced performance without proportionally increasing complexity.
Solution Approach 2:
The resonator elements are designed to serve multiple functions simultaneously - each resonator contributes to both the passband characteristics and the stopband rejection. The series and shunt resonators work together to provide both frequency selection and impedance transformation, reducing the need for additional dedicated components.
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 resonator filter achieves excellent filtration characteristics, high implementation efficiency, and effective heat dissipation, enabling a wide pass bandwidth while maintaining a compact size, suitable for modern mobile devices.
Implementation Method 1
a piezoelectric layer 150S, 150F disposed between the first electrode 140S, 140F and the second electrode 160S, 160F
Implementation Method 2
an acoustic resonator filter 50a, 50b according to at least one embodiment
Data Source
AI summary
An acoustic resonator filter is provided. The acoustic resonator filter includes a rear filter electrically connected between a front port and a rear port, through which a radio frequency (RF) signal passes, the rear filter including at least one film bulk acoustic resonator (FBAR); and a front filter electrically connected between the front port and the rear filter and including at least one solidly mounted resonator (SMR).