Tunable Piezoelectric Resonator Structure for Multi-Band Filtering

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Solution Overview

Problem

Conventional filters in communication devices require multiple discrete components to cover various frequency bands, leading to space and manufacturing challenges due to the need for filters with specific characteristics for different frequency bands and carrier aggregation, especially with fixed resonance designs.

Innovation Solution

A method for manufacturing coupled resonator structures using piezoelectric materials on different wafers, where a first wafer with a specific piezoelectric material is diced and bonded to a second wafer with another piezoelectric material, enabling acoustic coupling and tunability, allowing for the integration of materials with different properties and sizes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple discrete filters are used to cover different frequency bands, then frequency band coverage is improved, but device space consumption increases

Engineering Contradiction:

Improvefrequency band coverageVSAvoiddevice space

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

A single BAW filter device is designed to perform multiple filtering functions across different frequency bands by integrating coupled resonator structures with different acoustic impedances, eliminating the need for multiple discrete filters and reducing device space consumption

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of manufacture

If conventional BAW filters are used for fixed frequency bands, then manufacturing simplicity is improved, but adaptability to different frequency bands deteriorates

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidfrequency band adaptability

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The filter design incorporates coupled resonators where the effective acoustic impedance can be dynamically adjusted by changing the coupling strength between resonators with different acoustic impedances, allowing the same physical structure to adapt to different frequency bands while maintaining manufacturing simplicity

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The filter characteristics are made可调 by changing parameters such as the coupling coefficient between resonators and the acoustic impedance ratio, allowing a single manufactured filter to operate across multiple frequency bands without requiring different physical filters for each band

Inventive Principle:

Principle #35Parameter changes

3Reliability

If different piezoelectric materials are used for first and second resonators, then resonator performance is improved, but manufacturing difficulty increases

Engineering Contradiction:

Improveresonator performanceVSAvoidmanufacturing difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The filter is divided into two separate resonator components that can be manufactured independently using their optimal piezoelectric materials, then coupled together through acoustic interaction, allowing each resonator to be optimized for its specific material properties while simplifying the overall manufacturing process

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The coupling structure between the two resonators acts as an intermediary that enables acoustic energy transfer while allowing the resonators to be made from different materials with different acoustic impedances, thus achieving optimal performance for each resonator type without requiring complex multi-material integration

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach reduces the number of filters needed by enabling tunable filters with adjustable resonance frequencies, improving bandwidth coverage and reducing component count, while allowing for the use of larger wafers for increased production efficiency.

Implementation Method 1

processing a first wafer to form a processed first wafer, the processed first wafer comprising a first piezoelectric material, processing a second wafer to form a processed second wafer, the processed second wafer comprising a second piezoelectric material

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

processing the joint wafer to form a resonator structure comprising a first resonator including the first piezoelectric material and a second resonator including the second piezoelectric material such that the first and second resonators are acoustically coupled with each other

Methodology Applied

Scientific EffectAcoustic wave propagation: Sound

Data Source

PatentUS11233493B2Method for fabricating resonator structure and resonator structure

Publication Date: 2022.01.25 INFINEON TECHNOLOGIES AG

AI summary

Methods for manufacturing resonator structures and corresponding resonator structures are described. A first wafer including a first piezoelectric material is singulated and bonded to a second wafer.