Curved-Edge BAW Resonator Layout for Transverse Mode Suppression

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing bulk acoustic wave resonators suffer from energy loss due to transverse modes, which are not effectively suppressed by conventional shapes with parallel edges and right angles, leading to degraded performance.

Innovation Solution

A Cartesian curve configuration-based bulk acoustic wave resonator with symmetrical closed figures formed by Cartesian curves, such as cardioids, foliums, or ovals, is designed to increase the transmission distance of transverse waves, reducing energy loss and suppressing transverse modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional pentagonal resonator shape is used, then the resonator can be manufactured with simple processing, but transverse modes are not effectively suppressed causing energy loss and degraded performance

Engineering Contradiction:

Improveresonator performanceVSAvoidenergy loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies curved boundaries (circular, elliptical, or rounded rectangular shapes) instead of straight edges and right angles. This curvature increases the transmission distance of transverse waves, causing greater energy loss for parasitic modes and effectively suppressing them. The curved geometry transforms the resonator boundary to eliminate parallel edges, thereby reducing vibration nodes and improving Q value.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent introduces asymmetric or non-uniform curved boundaries that break the symmetry of conventional regular polygons. This asymmetry in the curved geometry further disrupts transverse wave propagation paths, increasing transmission distance and energy dissipation for parasitic modes while maintaining longitudinal mode efficiency.

Inventive Principle:

Principle #4Asymmetry

2Ease of manufacture

If a pentagonal resonator shape is used, then processing is relatively simple, but more vibration nodes are generated resulting in energy loss

Engineering Contradiction:

Improveprocessing easeVSAvoidvibration node complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The curved boundary geometry simplifies the vibration pattern by eliminating sharp corners and parallel edges that generate multiple vibration nodes. The smooth curved shape reduces the complexity of vibration modes while maintaining manufacturability through standard semiconductor fabrication processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Productivity

If parallel edges and right angles are used in resonator design, then manufacturing is easier, but transverse modes are not suppressed leading to degraded Q value

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidQ value

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent replaces parallel edges and right angles with continuous curved boundaries. This geometric transformation maintains compatibility with standard manufacturing processes while effectively suppressing transverse modes. The curved shape increases transverse wave transmission distance, resulting in greater energy dissipation and improved Q value without significantly complicating fabrication.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 resonator design significantly reduces energy loss and improves performance by minimizing vibration nodes and enhancing the Q value, while being easier to process and analyze.

Implementation Method 1

a resonator is generally designed in a shape without parallel edges and right angles... to suppress the generation of the transverse mode

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

During the operation of bulk acoustic wave resonators, longitudinal acoustic wave transmission is mainly utilized to complete the conversion of electrical energy-mechanical energy-electrical energy

Methodology Applied

Scientific EffectAcoustic wave transmission: Sound

Data Source

PatentUS12609673B2Cartesian curve configuration-based bulk acoustic wave resonator and bulk acoustic wave filter

Publication Date: 2026.04.21 HEYUAN AIFO LIGHT COMM TECH CO LTD

AI summary

Disclosed are a Cartesian curve configuration-based bulk acoustic wave resonator and a bulk acoustic wave filter, belonging to the technical field of resonators. The Cartesian curve configuration-based bulk acoustic wave resonator includes a substrate, a support layer, a bottom electrode, a piezoelectric layer, and a top electrode stacked sequentially, with a cavity disposed between the substrate and the support layer. Contour shapes of overlapping portions of the bottom electrode and the piezoelectric layer and of overlapping portions of the piezoelectric layer and the top electrode are both symmetrical closed figures and the closed figure is comprised of at least one Cartesian curve. The Cartesian curve configuration-based bulk acoustic wave resonator according to the present disclosure allows the resonator to generate fewer vibration nodes, thereby reducing energy loss and greatly improving the performance of the resonator.