SAW Resonator Buried Mass Loading for Spurious Mode Suppression

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Acoustic wave devices, such as SAW and BAW devices, face challenges in suppressing transverse mode spurious signals, which affect their performance and efficiency in radio frequency electronic systems.

Innovation Solution

The acoustic wave device incorporates high-density strips of materials within a dielectric film over interdigital transducer electrode fingers and in gap regions, strategically positioned to reduce spurious signal generation, with simulations showing optimal suppression when the strips are appropriately widthed and spaced.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-density strips are added to suppress transverse mode spurious signals, then signal suppression performance is improved, but device structure complexity increases

Engineering Contradiction:

Improvespurious signal suppressionVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The device is segmented into multiple functional regions with different strip configurations: edge regions contain first strips for temperature compensation, while gap regions contain second strips for spurious signal suppression. This segmentation allows each region to be optimized independently for its specific function, improving overall performance without uniformly increasing complexity across the entire device.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the device are assigned different strip characteristics: the first strips in edge regions have specific dimensions and materials optimized for temperature compensation, while the second strips in gap regions have different dimensions and positioning optimized for suppressing transverse mode spurious signals. This local differentiation enables targeted optimization of each region's quality characteristics.

Inventive Principle:

Principle #3Local quality

2Speed

If multiple strips with different materials are used to optimize acoustic velocity, then acoustic performance is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveacoustic velocityVSAvoidmanufacturing complexity

Core Design Contradiction:

SpeedVSEase of manufacture

Solution Approach 1:

The acoustic velocity is optimized by changing material parameters (density, elastic properties) of the strips in different regions. The first strips use materials with specific acoustic properties for temperature compensation, while the second strips use materials optimized for spurious signal suppression. By adjusting these material parameters locally, the overall acoustic velocity and device performance are optimized.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The device employs composite material structures where metal strips (such as molybdenum or tungsten) are integrated into dielectric layers. These composite structures combine the acoustic blocking properties of high-density metals with the electrical insulation and mechanical support of dielectric materials, achieving optimized acoustic velocity and spurious signal suppression through material composition rather than单一材料.

Inventive Principle:

Principle #40Composite materials

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 transverse spurious signals, enhancing the performance and efficiency of acoustic wave devices by optimizing acoustic velocity and resonance characteristics.

Implementation Method 1

acoustic wave devices, such as SAW and BAW devices

Methodology Applied

Scientific EffectAcoustic wave propagation: Surface Acoustic Wave

Implementation Method 2

first strips formed of a first material having a density greater than a density of the first dielectric film disposed within the first dielectric film over tips of the interdigitated electrode fingers

Methodology Applied

Scientific EffectDensity gradient effect: Density Gradient

Implementation Method 3

a substrate including a piezoelectric material, interdigital transducer (IDT) electrodes disposed on a surface of the substrate

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 4

optimizing acoustic velocity and resonance characteristics

Methodology Applied

Scientific EffectAcoustic resonance: Resonance

Data Source

PatentUS12261591B2Temperature compensated surface acoustic wave devices with multiple buried mass loading strips

Publication Date: 2025.03.25 SKYWORKS SOLUTIONS INC

AI summary

An acoustic wave device comprises a substrate including a piezoelectric material, interdigital transducer (IDT) electrodes disposed on a surface of the substrate, a first dielectric film having a lower surface disposed on the IDT electrodes and the surface of the substrate, first strips formed of a first material having a density greater than a density of the first dielectric film disposed within the first dielectric film over tips of the interdigitated electrode fingers in the edge regions of the IDT electrodes, and second strips formed of a second material having a density greater than the density of the first dielectric film disposed within the first dielectric film in the gap regions of the IDT electrodes, laterally spaced from the first strips in a direction perpendicular to a direction of propagation of a main acoustic wave through the acoustic wave device, and extending only partially over the gap regions.