Stacked Acoustic Resonator Filter for Electrical Frequency Tuning
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Solution Overview
Problem
Existing ferroelectric acoustic resonators in wireless devices lack the ability to be electrically controlled to operate at desired frequencies without altering their inner structure, limiting their adaptability in high-frequency applications.
Innovation Solution
A tunable acoustic resonator filter structure is developed, comprising a stacked configuration of a series resonator filter die and a tunable shunt coupled resonator filter (CRF) die, allowing for electrical control of the resonator's frequency without modifying its inner structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the inner structure of the ferroelectric acoustic resonator is changed to adjust the operating frequency, then the operating frequency can be tuned, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent replaces mechanical/physical structural modifications with electrical control mechanisms. Specifically, it uses electric field application through control electrodes to tune the resonant frequency of the acoustic resonator, substituting what would traditionally require changing the physical dimensions or material properties of the resonator. This allows frequency tuning without altering the inner structure, resolving the contradiction between adaptability and device complexity
Solution Approach 2:
The patent changes the electrical parameters (electric field strength, voltage) applied to the ferroelectric acoustic resonator to tune its operating frequency. By modifying the electrical state rather than physical dimensions, the system achieves frequency adaptability while maintaining structural integrity and simplifying manufacturing. The control electrodes apply varying electric fields to dynamically adjust the resonant frequency according to different working conditions
2Adaptability or versatility
If multiple acoustic resonator filter structures are integrated in an acoustic ladder filter network, then the filter network functionality is enhanced, but the footprint area increases
Solution Approach 1:
The patent transitions from a planar two-dimensional layout to a three-dimensional stacked configuration. Multiple acoustic resonator filter structures are arranged vertically in layers rather than horizontally in a single plane. This dimensional change allows multiple filter functions to be integrated within a compact footprint, as the structures occupy different vertical spaces (z-dimension) while sharing the same horizontal area, thus enhancing filter network functionality without proportionally increasing the footprint area
Solution Approach 2:
The patent implements a nested or layered arrangement where multiple acoustic resonator filter structures are stacked one above another, with lower-layer structures serving as foundations for upper-layer structures. This nesting approach allows compact integration of multiple filter functions in a vertical stack, maximizing the use of three-dimensional space and reducing the overall footprint area while maintaining enhanced filter network functionality
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 solution enables the acoustic resonator filter structure to be compactly integrated into acoustic ladder filter networks, enhancing the flexibility and efficiency of wireless devices in high-frequency applications.
Implementation Method 1
The series resonator filter die is configured to resonate at a series resonance frequency to pass a signal from an input node to an output node
Implementation Method 2
The tunable shunt CRF die is configured to resonate at a tunable parallel resonance frequency to block the signal between the input node and the output node
Data Source
AI summary
An acoustic resonator filter structure with a tunable shunt coupled resonator filter (CRF) is provided. Herein, the acoustic resonator filter structure is a stacked structure that includes a series resonator filter die and a tunable shunt CRF die. By stacking the series resonator filter die and the tunable shunt CRF die according to various embodiments, it is possible to reduce a footprint of the acoustic resonator filter structure, thus making it possible to incorporate multiple acoustic resonator filter structures in an acoustic ladder filter network.