Coupled Bulk Acoustic Resonators for Steep Filter Transition Bands

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Solution Overview

Problem

Conventional bulk acoustic wave devices suffer from poor transition band performance and harmonic generation at high power levels, with manufacturing complexities and size constraints in existing filter designs.

Innovation Solution

A bulk acoustic wave device comprising first and second resonators acoustically coupled and electrically connected in parallel, allowing for a single resonance frequency and improved harmonic cancellation, while reducing chip area and manufacturing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional bulk acoustic wave devices are used, then manufacturing is simpler, but transition band performance is poor and harmonic generation occurs at high power levels

Engineering Contradiction:

Improvetransition band performanceVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The device is divided into multiple resonators (first resonator, second resonator, and additional resonators) that are acoustically coupled and electrically connected in parallel. Each resonator can be independently designed and optimized, allowing for complex filtering functionality to be achieved through modular assembly rather than a single complex structure

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple resonators are combined in a coupled configuration where they share acoustic energy through acoustic coupling while maintaining electrical parallel connection. This merging of multiple simple resonator units creates a composite structure that achieves superior transition band performance and harmonic cancellation that would be difficult to obtain with a single resonator

Inventive Principle:

Principle #5Merging (Combining)

2Area of stationary object

If conventional filter designs are used, then device structure is simpler, but chip area is larger

Engineering Contradiction:

Improvechip areaVSAvoidfilter design complexity

Core Design Contradiction:

Area of stationary objectVSDevice complexity

Solution Approach 1:

The resonators are arranged in a compact coupled configuration where they share common acoustic pathways and structural elements. The acoustic coupling mechanism allows resonators to be closely integrated, nesting their functional spaces and reducing the overall chip area compared to conventional designs where each resonator would require separate, non-shared space

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The coupled resonator structure serves multiple functions simultaneously: it provides frequency filtering, harmonic cancellation, and impedance matching all within a single integrated configuration. This multi-functionality eliminates the need for separate components that would otherwise be required in conventional designs, reducing total chip area

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Object-generated harmful factors

If conventional resonator configurations are used, then manufacturing is easier, but harmonic generation occurs at high power levels

Engineering Contradiction:

Improveharmonic generationVSAvoidresonator configuration

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The acoustic coupling between resonators is used to convert the harmful harmonic generation into beneficial harmonic cancellation. The coupled resonators are designed so that their acoustic interactions naturally produce cancellation effects at harmonic frequencies, transforming what would be unwanted byproducts into a feature that improves overall device performance

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The resonator system functions as a composite acoustic structure where multiple resonator units with different characteristics are combined. This composite configuration creates destructive interference patterns for harmonics while maintaining constructive interference for the fundamental frequency, effectively filtering harmonics through the composite structure's acoustic properties

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 provides superior size and electrical performance with steep transition bands and reduced harmonic generation, making it easier to manufacture and more efficient than conventional solutions.

Implementation Method 1

each comprising a first electrode, a piezoelectric layer formed at least partially on the first electrode, and a second electrode formed at least partially on the piezoelectric layer

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect