Piezoelectric Resonator C-Axis Reorientation for Harmonic Cancellation
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Solution Overview
Problem
Existing resonators face challenges in controlling the direction of the compression axis vector (C-axis) of piezoelectric materials, limiting design flexibility and performance in applications like RF filters.
Innovation Solution
A method involving the fabrication of a resonator with a piezoelectric material having an initial C-axis vector orientation, followed by the application of an electric field to modify the direction of the C-axis vector to a desired orientation, such as antiparallel, enhancing electromechanical coupling and harmonic cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the C-axis vector direction of piezoelectric material is controlled during fabrication, then design flexibility of resonator is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by establishing a desired C-axis vector orientation in the piezoelectric material during the fabrication process itself, rather than attempting to modify it later. This is achieved through controlled deposition techniques that inherently orient the crystalline structure, thereby achieving design flexibility while avoiding the complexity of post-fabrication modification processes.
Solution Approach 2:
The patent utilizes parameter changes by controlling fabrication parameters such as deposition temperature, pressure, and material composition to achieve the desired C-axis vector orientation. By adjusting these parameters during fabrication, the piezoelectric material develops the required directional properties inherently, resolving the contradiction between design flexibility and manufacturing complexity.
2Reliability
If electric field is applied to modify C-axis vector direction after fabrication, then electromechanical coupling coefficient is improved, but additional processing steps are required
Solution Approach 1:
The patent merges the C-axis vector modification process with the existing fabrication process by applying the electric field during or immediately after material deposition, rather than as a separate post-processing step. This integration achieves improved electromechanical coupling coefficient while minimizing additional processing steps, as the same equipment and procedures used for fabrication are utilized for the field application.
3Reliability
If C-axis vector orientation is modified to achieve harmonic cancellation, then filter performance is improved, but fabrication precision requirements increase
Solution Approach 1:
The patent applies self-service by designing a fabrication process where the piezoelectric material inherently develops the required C-axis vector orientation through controlled deposition conditions. The material's crystalline structure self-organizes during fabrication to achieve the desired orientation for harmonic cancellation, thereby improving filter performance without requiring extremely tight external control or post-fabrication adjustment, thus reducing fabrication precision requirements.
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 approach allows for improved design flexibility and performance by achieving consistent electromechanical coupling coefficients and effective suppression of harmonic modes, enabling operation at higher frequencies with reduced losses.
Implementation Method 1
a piezoelectric material may expand or contract along a compression axis (C-axis) in response to an applied voltage, where the C-axis is typically based on an orientation of a crystalline structure of the piezoelectric material
Implementation Method 2
applying an electric field across the piezoelectric material to modify a direction of the C-axis vector to be oriented along a second direction different than the first direction
Implementation Method 3
such resonators may exhibit acoustic resonant modes (e.g., resonant frequencies, resonances, or the like) that may be exploited to provide desired properties when implemented within an electronic circuit such as, but not limited to, a filter
Data Source
AI summary
A resonator may include a first electrode, a second electrode, and a piezoelectric material between the first electrode and the second electrode, where the piezoelectric material is formed by fabricating the piezoelectric material with a compression axis vector (C-axis vector) oriented along a first direction and applying an electric field across the piezoelectric material to modify a direction of the C-axis vector to be oriented along a second direction. The second direction may be antiparallel to the first direction.