Lateral Field Acoustic Resonator Structure for Heat and Coupling
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Solution Overview
Problem
Existing acoustic resonators face challenges in high-frequency applications due to poor thermal dissipation and reduced coupling, particularly in surface acoustic wave (SAW) and bulk acoustic wave (BAW) filters, which impact performance and power handling.
Innovation Solution
A lateral field excitation acoustic resonator design with electrodes positioned between a piezoelectric membrane and a substrate, featuring an air gap and alternating layers of low and high acoustic impedance materials, enhancing thermal dissipation and coupling while minimizing parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If electrodes are placed directly on the substrate in conventional acoustic resonators, then the structure is simple, but thermal dissipation is poor and coupling is reduced
Solution Approach 1:
The patent positions electrodes in the air gap between the piezoelectric membrane and substrate, transitioning from a planar configuration to a three-dimensional spatial arrangement. This dimensional change allows electrodes to be placed in a previously unused space, improving thermal dissipation and coupling without significantly increasing overall device complexity
Solution Approach 2:
The air gap acts as an intermediary medium between the electrodes and the piezoelectric membrane, enabling better thermal management and electroacoustic coupling. The air gap serves as a mediator that allows electrodes to excite lateral field acoustic waves more effectively while facilitating heat dissipation
2Power
If conventional electrode configurations are used, then manufacturing is straightforward, but electroacoustic coupling is reduced
Solution Approach 1:
The piezoelectric membrane is bonded to the substrate on structures that are already present during the manufacturing process. This preliminary action of bonding to existing structures simplifies the overall manufacturing process while enabling the advanced electrode configuration for improved coupling
Solution Approach 2:
By placing electrodes in the air gap rather than on the substrate surface, the patent creates a new spatial configuration that enhances electroacoustic coupling. This three-dimensional arrangement allows for better field excitation while maintaining manufacturing feasibility through standard bonding processes
3Object-affected harmful factors
If standard resonator designs are used, then the device is compact, but parasitic capacitance increases at high frequencies
Solution Approach 1:
The air gap serves as an electrical intermediary that reduces parasitic capacitance between the electrodes and the piezoelectric membrane. This intermediate space minimizes unwanted capacitive coupling, enabling the resonator to operate effectively at higher frequencies without the performance degradation caused by parasitic effects
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 design achieves improved thermal dissipation and high electroacoustic coupling, supporting efficient operation at high frequencies with reduced stray capacitance and enhanced performance in filters like ladder filters.
Implementation Method 1
a piezoelectric membrane for which excitation is done using electrodes at alternate polarities
Implementation Method 2
When a voltage is applied to the electrodes, lateral field acoustic waves are excited in the resonating material
Data Source
AI summary
Lateral field excitation acoustic resonators and methods of manufacture are disclosed. In one aspect, an acoustically resonating material such as a piezoelectric film or membrane is spaced from a substrate by electrodes having an air gap therebetween. When current flows through the electrodes, lateral field acoustic waves are excited in the resonating material with relatively good coupling and adequate heat dissipation.