Interdigital Transducer Electrode Layout for Higher Acoustic Frequency
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Solution Overview
Problem
Existing acoustic wave devices face challenges in manufacturing complexity due to the need for precise alignment of multiple electrode sets on both sides of a substrate, leading to propagation losses and increased manufacturing constraints.
Innovation Solution
The interdigital transducer design features a substrate with alternating high and low surface portions, where first and second sets of elongate electrodes are alternately adjacent to each other, reducing the need for complex alignment and allowing for increased propagation frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple sets of electrodes are applied on different sides of the substrate to improve frequency and quality, then the working frequency and quality factor are improved, but the manufacturing complexity increases due to precise alignment requirements
Solution Approach 1:
The patent combines multiple electrode sets into a single substrate surface arrangement. Instead of applying electrodes on both sides of the substrate requiring precise alignment, the invention integrates first and second sets of electrodes on the same surface, alternating between high and low surface portions, eliminating the need for complex multi-side alignment while maintaining the frequency and quality factor improvements
Solution Approach 2:
The patent utilizes the vertical dimension by creating alternating high and low surface portions on the substrate. This dimensional approach allows electrodes to be arranged in a three-dimensional pattern on a single surface, effectively packing multiple electrode sets without requiring placement on both sides of the substrate, thus simplifying manufacturing while achieving the desired frequency multiplication
2Speed
If electrodes are placed closer together to increase propagation frequency, then the working frequency increases, but the manufacturing precision requirements increase
Solution Approach 1:
The patent segments the electrode arrangement into distinct high and low surface portions with alternating patterns. This segmentation allows each electrode set to be positioned on predetermined substrate regions, reducing the need for high-precision alignment between adjacent electrodes while maintaining the close spacing required for high propagation frequency
Solution Approach 2:
The patent employs preliminary patterning of the substrate into high and low surface portions before electrode deposition. This preliminary action creates predetermined positions for electrodes, reducing the precision requirements during the actual electrode placement process while enabling closer electrode spacing for increased propagation frequency
3Ease of manufacture
If large vertical separation between electrode sets is used to simplify manufacturing, then the manufacturing process is simplified, but propagation losses increase
Solution Approach 1:
The patent resolves this contradiction by utilizing vertical surface portions (high and low regions) on the same substrate plane rather than separating electrodes vertically across the substrate thickness. This dimensional approach maintains small effective separation distances between electrode sets, reducing propagation losses while keeping all electrodes on one side for manufacturing simplicity
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 design simplifies the manufacturing process while achieving a doubled working frequency and improved quality factor, reducing impedance and enhancing the efficiency of the acoustic wave device.
Implementation Method 1
The substrate is made of any one of aluminum nitride, doped aluminum nitride, in particular scandium doped aluminum nitride, zinc oxide, lithium niobite, or any suitable piezoelectric material
Data Source
AI summary
An interdigital transducer increased propagation frequency and a method for making the same is described. The transducer comprises a substrate for propagation of acoustic waves comprising a first surface having alternating high and low surface portions extending laterally across the substrate, a set of elongate first electrodes, each first electrode disposed on a respective high surface portion and a set of elongate second electrodes, each second electrode disposed on a respective low surface portion such that the first and second electrodes are alternately adjacent to one another, the high and low surface portions being substantially equal in width to each electrode of the first and second sets of electrodes.