Interdigital Resonator Electrode Structure for Spurious Mode Suppression
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Solution Overview
Problem
Interdigital resonators face issues such as spurious modes causing in-band ripple, poor heat dissipation due to low thermal conductivity, and brittleness leading to potential fractures during manufacturing, which affect their performance in high-frequency, large bandwidth applications like 5G and 6G radio frequency filters.
Innovation Solution
The interdigital resonator incorporates a double-layer electrode structure with scattering structures and scattering media having different acoustic impedances to suppress spurious modes, enhance heat dissipation, and improve power capacity by increasing thickness and structural support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If scattering structures with different acoustic impedance media are added to suppress spurious modes, then filter performance is improved, but device complexity increases
Solution Approach 1:
The patent introduces scattering holes within the electrode structure that are filled with scattering media having different acoustic impedances. This porous configuration creates acoustic scattering effects that suppress spurious modes while maintaining a relatively compact overall structure, thus improving filter performance without proportionally increasing device complexity
Solution Approach 2:
The patent employs composite electrode structures where different materials with distinct acoustic impedance characteristics are combined within the same electrode assembly. This use of composite materials enables effective spurious mode suppression through acoustic impedance contrast while integrating multiple functions within a unified structure
2Power
If piezoelectric layer thickness is increased to improve power capacity, then power handling capability is improved, but manufacturing difficulty increases due to brittleness
Solution Approach 1:
The patent adopts composite electrode structures with optimized material compositions and layered configurations that enhance the mechanical strength and fracture resistance of the piezoelectric assembly. This allows for increased effective thickness for power handling while maintaining manufacturability through improved structural integrity
Solution Approach 2:
The patent employs flexible interconnection structures and optimized electrode geometries that reduce mechanical stress concentration in the piezoelectric layer. This enables the use of thicker piezoelectric materials for enhanced power capacity while preventing manufacturing defects caused by excessive brittleness
3Ease of manufacture
If electrode structure is simplified to reduce manufacturing complexity, then ease of manufacture is improved, but heat dissipation performance deteriorates
Solution Approach 1:
The patent implements localized thermal management features within the electrode structure, such as strategically positioned heat dissipation pathways and thermally conductive materials at critical locations. This allows for effective heat dissipation in specific high-power regions while keeping the overall electrode structure relatively simple and manufacturable
Solution Approach 2:
The patent introduces thermal interface materials and heat spreader structures that act as intermediaries between the piezoelectric layer and heat sinks. These intermediary elements facilitate efficient heat transfer without requiring complex direct thermal coupling, thus maintaining manufacturing simplicity while improving heat dissipation
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 solution effectively suppresses spurious modes, improves heat dissipation, and enhances power capacity, achieving a maximum input power of 35.08 dBm, compared to 24.76 dBm in prior art, while reducing ohmic loss and manufacturing complexity.
Implementation Method 1
the scattering structure includes scattering holes and a scattering medium provided in each of the scattering holes, the scattering hole penetrates through at least a part of the double-layer electrode structure, and an acoustic impedance of the scattering medium is different from an acoustic impedance of an electrode layer where the scattering medium is located
Implementation Method 2
The interdigital resonator includes an interdigital transducer and a piezoelectric layer
Data Source
AI summary
Disclosed are an interdigital resonator and a filter. The interdigital resonator includes a piezoelectric layer and an interdigital transducer located on one side of the piezoelectric layer. The electrode fingers include a double-layer electrode structure and at least one scattering structure provided in the double-layer electrode structure. The double-layer electrode structure includes at least two laminated electrode layers. The scattering structure includes scattering holes and scattering media provided in the scattering holes. The scattering holes penetrate through at least a part of the double-layer electrode structure. The acoustic impedance of the scattering medium is different from the acoustic impedance of an electrode layer where the scattering medium is located.