Piezoelectric Acoustic Isolator Structure for Breakdown-Resistant Isolation
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Solution Overview
Problem
Piezoelectric materials used in isolators have poor dielectric characteristics, leading to high electric fields and low dielectric strength, making them susceptible to electric breakdown and inefficient in isolating signals.
Innovation Solution
Incorporating dielectric material layers with lower dielectric constants between piezoelectric transmitters and receivers, and using acoustic reflectors and absorbers to control surface acoustic wave propagation, thereby reducing local electric fields and increasing breakdown strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If piezoelectric materials are used in isolators, then signal transmission capability is improved, but dielectric strength decreases leading to susceptibility to electric breakdown
Solution Approach 1:
The patent employs composite material structures combining piezoelectric materials with dielectric materials having lower dielectric constants. The piezoelectric material (e.g., lithium niobate, zinc oxide, gallium nitride) provides signal transmission capability while the dielectric material layer reduces local electric field concentration, creating a composite structure that achieves both high isolation efficiency and adequate dielectric strength
Solution Approach 2:
A dielectric material layer is introduced as an intermediary between the piezoelectric transmitter and receiver electrodes. This intermediate layer has lower dielectric constant than the piezoelectric material, serving to reduce electric field concentration and prevent breakdown while allowing acoustic wave propagation to continue effectively
2Power
If piezoelectric materials with high dielectric constant are used, then piezoelectric effect efficiency is improved, but electric field concentration increases leading to breakdown
Solution Approach 1:
The patent applies local quality modification by introducing a dielectric material layer with different properties (lower dielectric constant) at specific locations where electric field concentration occurs. The piezoelectric material maintains its high dielectric constant properties in regions where piezoelectric effect efficiency is needed, while the dielectric layer is placed strategically to reduce electric field concentration and prevent breakdown
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
Enhances isolation efficiency by minimizing high electric fields and preventing breakdown, ensuring stable operation and effective signal transmission.
Implementation Method 1
The piezoelectric effect is a phenomenon by which certain materials generate an electric charge when mechanical stress is applied to them. Conversely, these materials also exhibit mechanical deformation in response to an applied electric field.
Implementation Method 2
In some embodiments, the piezoelectric material has a first dielectric constant and the first dielectric material layer has a second dielectric constant less than the first dielectric constant.
Implementation Method 3
The inventors have developed techniques for promoting propagation of surface acoustic waves toward the receiver while limiting propagation in the opposite direction.
Data Source
AI summary
Described herein are techniques for enhancing isolation in on-chip piezoelectric-based isolators. Several techniques are described that improve isolation in piezoelectric isolators. According to an aspect of the present disclosure, a piezoelectric isolator may include structures arranged to decrease the occurrence of pockets of high electric field and/or to increase the breakdown electric field in the path from the transmitter to the receiver. Further aspects of the present disclosure relate to techniques for increasing the efficiency of piezoelectric isolators while also limiting the formation of spurious signals. The inventors have developed techniques for promoting propagation of surface acoustic waves toward the receiver while limiting propagation in the opposite direction.