Dual-Layer SAW IDT Electrodes for Lower Intermodulation Distortion
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Solution Overview
Problem
Existing surface acoustic wave (SAW) devices face challenges in achieving improved nonlinearity and reduced higher-order signal components, particularly in 5G communication systems where intermodulation issues arise due to high signal levels, necessitating enhanced electrode structures and materials.
Innovation Solution
A dual-structure interdigital transducer (IDT) electrode with a lower electrode made of tungsten or chromium, having a hardness between 12 GPa and 16 GPa, and an upper electrode of aluminum-copper alloy, along with a bonding enhancement layer, to improve nonlinearity and reduce higher-order signal components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-structure IDT electrode is used, then the device structure is simple, but the nonlinearity is insufficient and higher-order signal components are not reduced
Solution Approach 1:
The IDT electrode is segmented into multiple functional layers: a lower electrode (first electrode) and an upper electrode (second electrode) with different material compositions and properties. This segmentation allows each layer to contribute different characteristics, improving overall nonlinearity while managing structural complexity through functional division.
Solution Approach 2:
The patent employs composite material structure by combining different materials for the lower and upper electrodes. The lower electrode uses materials with specific hardness (12-16 GPa) and elastic modulus (≥320 GPa), while the upper electrode uses different materials, creating a composite structure that optimizes nonlinearity and reduces higher-order signal components.
2Object-generated harmful factors
If the signal level and voltage input to the SAW resonator are lowered, then intermodulation signals are reduced, but the power and signal strength decrease
Solution Approach 1:
The patent changes the physical parameters of the electrode materials, specifically selecting materials with optimized hardness (12-16 GPa) and elastic modulus (≥320 GPa) for the lower electrode. This parameter optimization allows the electrode to operate with reduced nonlinearity, enabling lower signal levels and voltages while maintaining adequate power output and reducing intermodulation distortion.
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 improved electrode structure enhances nonlinearity, providing a wider elastic deformation range and reduced harmonic levels, thus mitigating intermodulation distortion in 5G communication systems.
Implementation Method 1
the hardness of the lower electrode is between 12 GPa and 16 GPa... the elasticity modulus of the lower electrode may be greater than or equal to 320 GPa... providing a wider elastic deformation range and reduced harmonic levels
Implementation Method 2
A surface acoustic wave device is an electromechanical device that utilizes the interaction between these surface acoustic waves and conductive electrons, making use of surface acoustic waves transmitted on the surface of a piezoelectric crystal
Data Source
AI summary
A surface acoustic wave device having an electrode structure with improved nonlinearity, a filter including the same, and a method for manufacturing the surface acoustic wave device are provided. The surface acoustic wave device comprises a piezoelectric substrate and a plurality of IDT electrodes formed on the piezoelectric substrate, wherein each of the plurality of IDT electrodes comprises a lower electrode formed on a surface of the piezoelectric substrate and an upper electrode formed on the lower electrode, and wherein the lower electrode has a hardness of 12 GPa to 16 GPa.