Bulk Acoustic Wave Filter Using Overtone Resonators for High RF Power

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Solution Overview

Problem

Existing acoustic wave filters struggle to achieve high resonant frequencies while maintaining effective power handling, particularly in radio frequency electronic systems.

Innovation Solution

The development of acoustic wave filters that incorporate bulk acoustic wave resonators with overtone modes, utilizing stacked piezoelectric layers with different c-axis orientations to achieve higher resonant frequencies and improved power handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If acoustic wave resonators use conventional fundamental mode operation, then power handling capability is maintained, but resonant frequency is limited

Engineering Contradiction:

Improveresonant frequencyVSAvoidpower handling capability

Core Design Contradiction:

SpeedVSPower

Solution Approach 1:

The patent changes the operational mode parameter from fundamental mode to overtone mode (specifically second or third overtone modes at 4 GHz or 6 GHz), which enables higher resonant frequencies while maintaining power handling capability through proper resonator design and stacking configurations

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite piezoelectric layer structures with alternating c-axis orientations (e.g., <001> and <111> orientations) to create resonators that can operate in overtone modes while maintaining mechanical strength and power handling capabilities

Inventive Principle:

Principle #40Composite materials

2Speed

If acoustic wave resonators are designed for high resonant frequency operation, then frequency performance is improved, but power handling capability deteriorates

Engineering Contradiction:

Improveresonant frequencyVSAvoidpower handling reliability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent divides the resonator structure into multiple piezoelectric layers with different c-axis orientations, where each layer contributes to the overall resonant frequency while the distributed structure handles power more effectively than a single thick layer

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent utilizes the dimensional aspect of stacking multiple thin piezoelectric layers vertically to achieve high resonant frequencies, while the horizontal distribution of stress across multiple layers improves power handling reliability

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

These filters can achieve resonant frequencies in the range of 5 GHz to 20 GHz, providing enhanced power handling and linearity, suitable for high-power applications in 5G New Radio systems.

Implementation Method 1

a first plurality of stacked piezoelectric layers positioned between a pair of first electrodes. The first bulk acoustic wave resonator is configured to excite an overtone mode

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The first bulk acoustic wave resonator is configured to excite an overtone mode as a main mode of the first bulk acoustic wave resonator

Methodology Applied

Scientific EffectAcoustic resonance: Resonance

Data Source

PatentUS12289097B2Acoustic wave filter with overtone mode resonator and fundamental mode resonator

Publication Date: 2025.04.29 SKYWORKS GLOBAL PTE LTD

AI summary

Aspects of this disclosure relate to acoustic wave filters with bulk acoustic wave resonators. An acoustic wave filter can include a first bulk acoustic wave resonator configured to excite an overtone mode as a main mode and a second bulk acoustic wave resonator having a fundamental mode as a main mode.