Resonator Bus Bar Connection With Air Gap for Lower Insertion Loss
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Solution Overview
Problem
Existing acoustic wave filters face challenges in minimizing resistive losses in electrical connections between resonators due to small gaps, which contribute to insertion losses, especially when miniaturization is critical.
Innovation Solution
Implementing a conductive structure with a first portion electrically connected to a bus bar and a second portion spaced from the fingers by an air gap, allowing for reduced resistive losses and improved performance by maintaining a clean frequency response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the gap between resonators is reduced to minimize device size, then device miniaturization is achieved, but resistive losses in electrical connections increase
Solution Approach 1:
The conductive structure extends in the lateral dimension by positioning the second portion over the active region of the interdigital transducer electrode, rather than only in the longitudinal direction. This dimensional change allows the electrical connection to span larger effective area, reducing resistive losses while maintaining compact longitudinal footprint for device miniaturization
Solution Approach 2:
The conductive structure merges two functional elements: the first portion provides electrical connection to the bus bar, while the second portion extends over the active region to reduce resistive losses. This merging of connection and loss-reduction functions into a single integrated structure achieves both miniaturization and low loss
2Loss of energy
If a conductive structure is positioned over the active region to reduce resistive losses, then insertion losses are reduced, but the risk of interfering with acoustic wave generation increases
Solution Approach 1:
The conductive structure acts as an intermediary element that is strategically positioned to reduce resistive losses without directly contacting the interdigital transducer electrode fingers. The air gap or dielectric spacer serves as a mediator that allows electrical connection while preventing direct interference with the acoustic wave generation process
Solution Approach 2:
The conductive structure is selectively positioned only over the active region where resistive losses are most significant, rather than covering the entire electrode structure. This localized placement reduces losses where needed while leaving the finger regions free to generate acoustic waves without interference
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 conductive structure with an air gap between the second portion and the fingers enhances the acoustic wave system's performance by reducing insertion losses and maintaining a clean frequency response, thus improving the overall efficiency of the acoustic wave devices.
Implementation Method 1
a conductive structure including a first portion at least partially positioned on the bus bar and a second portion at least partially positioned over the finger, the second portion spaced from the finger
Implementation Method 2
A surface acoustic wave resonator can include an interdigital transductor electrode on a piezoelectric substrate. The surface acoustic wave resonator can generate a surface acoustic wave on a surface of the piezoelectric layer
Data Source
AI summary
A method of forming an acoustic wave system including a resonator is disclosed. The method can include providing a patterned sacrificial layer over an active region of the resonator, forming a conductive structure including a first portion on a bus bar of the resonator and a second portion at least partially over the patterned sacrificial layer, and removing the patterned sacrificial layer.