Acoustic Resonator Filter Layout for Wide Bandwidth and Sharp Skirts
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Solution Overview
Problem
Current acoustic resonator filters face challenges in achieving a balance between wide pass bandwidth and sharp skirt characteristics, particularly in small and lightweight devices such as mobile communication devices, where existing designs often result in split pass bandwidth due to significant differences between resonance and anti-resonance frequencies.
Innovation Solution
The acoustic resonator filter incorporates a series unit with at least one series acoustic resonator connected in series between ports, accompanied by first and second shunt units with shunt acoustic resonators having different resonance frequencies, and a third shunt unit with resonators having lower resonance frequencies, along with increased inductance in the second shunt unit to compensate for bandwidth splitting and enhance skirt characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional acoustic resonator filter designs are used, then the device achieves basic filtering function, but the pass bandwidth becomes split and skirt characteristics become weak
Solution Approach 1:
The filter is divided into multiple resonator units with different resonance frequencies (first, second, and third resonators) arranged in specific series and shunt configurations. This segmentation allows each resonator to contribute to different frequency regions, enabling simultaneous achievement of wide pass bandwidth and sharp skirt characteristics without bandwidth splitting
Solution Approach 2:
The invention changes the resonance frequency parameters of different resonators to specific relationships (first resonator: f1, second resonator: f2 where f2 > f1, third resonator: f3 where f3 < f2). By carefully controlling these frequency parameters and their relationships, the filter achieves both wide pass bandwidth and sharp skirt characteristics while avoiding bandwidth splitting
2Ease of operation
If the filter is designed for wide pass bandwidth, then signal transmission is improved, but skirt characteristics become weak
Solution Approach 1:
The filter structure is segmented into multiple resonators with different resonance frequencies arranged in series and shunt configurations. This segmentation enables each resonator to target specific frequency regions, allowing the filter to simultaneously achieve wide pass bandwidth for signal transmission and sharp skirt characteristics for frequency selectivity
Solution Approach 2:
The invention optimizes the resonance frequency parameters of different resonators (f1, f2, f3) and their interrelationships to achieve the dual goal of wide pass bandwidth and sharp skirt characteristics. The specific parameter relationships ensure that the filter maintains both broad signal transmission and precise frequency discrimination
3Volume of moving object
If compact design is implemented, then device size is reduced, but performance balance between bandwidth and skirt characteristics deteriorates
Solution Approach 1:
The filter is segmented into multiple resonator units that can be arranged in a compact configuration. This segmentation allows efficient use of space while maintaining the complex frequency response characteristics needed for both wide pass bandwidth and sharp skirt characteristics, thus achieving performance balance in a compact form factor
Solution Approach 2:
The resonators are arranged in nested or integrated configurations where multiple resonant elements coexist in a compact structure. This nesting approach allows the filter to maintain complex frequency response characteristics for optimal performance while minimizing overall 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
This configuration results in a wider pass bandwidth and sharper skirt characteristics, efficiently balancing the two, thus meeting the performance standards required for modern mobile devices while maintaining a compact and lightweight design.
Implementation Method 1
an acoustic resonator such as a bulk acoustic wave (BAW) filter
Implementation Method 2
an acoustic resonator such as a bulk acoustic wave (BAW) filter
Implementation Method 3
acoustic resonator filter includes: a series unit including at least one series acoustic resonator
Data Source
AI summary
An acoustic resonator filter includes: a series unit including at least one series acoustic resonator electrically connected, in series, between first and second ports configured to pass a radio frequency (RF) signal; a first shunt unit disposed on a first shunt connection path between the at least one series acoustic resonator and a ground, the first shunt unit including a plurality of shunt acoustic resonators connected to each other in series and having different resonance frequencies; and a second shunt unit disposed in a second shunt connection path between the at least one series acoustic resonator and the ground, the second shunt unit including at least one shunt acoustic resonator and having higher inductance than inductance of the first shunt unit.