Dual-Mode MEMS Resonator Electrode Layout for Low Support Loss

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Solution Overview

Problem

Existing MEMS resonators face challenges in maintaining low support loss for both low and high temperature coefficient of frequency modes, especially in compact designs, leading to hysteresis and larger footprints due to modal interactions.

Innovation Solution

The use of compact dual-mode resonators with a shared resonator body, strategically positioned electrodes, and decoupling structures to minimize modal interactions and support loss, allowing selective transduction of each mode without affecting the other.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If two separate resonators are used for low TCF and high TCF modes, then temperature compensation can be achieved, but the device footprint increases and hysteresis occurs due to modal interactions

Engineering Contradiction:

Improvetemperature compensation capabilityVSAvoiddevice footprint

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent combines two separate resonators into a single integrated resonator structure that supports both low TCF and high TCF modes. The resonator body is designed with specific geometric features (e.g., annular shape with radial arms) that enable multiple vibration modes to coexist in one device, eliminating the need for separate resonators and reducing the overall footprint while maintaining temperature compensation capability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The resonator is segmented into distinct vibration zones with different mode shapes. The low TCF mode involves radial expansion/contraction of the annular body, while the high TCF mode involves flexural vibrations of the radial arms. This segmentation allows each mode to be independently controlled through strategically placed electrodes, enabling simultaneous operation without significant modal interaction

Inventive Principle:

Principle #1Segmentation

2Area of stationary object

If compact dual-mode resonator is used, then footprint is reduced, but support loss increases for both modes

Engineering Contradiction:

Improvedevice footprintVSAvoidsupport loss

Core Design Contradiction:

Area of stationary objectVSLoss of energy

Solution Approach 1:

The patent applies local quality by positioning electrodes at specific locations on the resonator body where they can selectively excite and sense either the low TCF mode or the high TCF mode without significantly coupling to the other mode. This localized electrode placement minimizes modal interaction and reduces support loss for both modes, achieving low support loss in a compact design

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The resonator body acts as an intermediary structure that decouples the two vibration modes. By designing the resonator with specific geometric features (e.g., radial arms connected to an annular body), the structure naturally isolates the low TCF and high TCF modes, allowing them to operate independently with minimal energy loss to the other mode

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If separate resonators are used for each mode, then modal interactions are avoided, but hysteresis occurs and footprint increases

Engineering Contradiction:

Improvemodal interaction isolationVSAvoiddevice structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The resonator is designed as a universal structure that performs multiple functions: it supports both low TCF and high TCF vibration modes, provides temperature sensing, and enables temperature compensation. The single resonator body with its specific geometry (annular shape with radial arms) and strategically placed electrodes can independently generate and detect both modes, eliminating the need for separate resonators and reducing overall device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 design achieves reduced hysteresis, smaller footprint, and improved performance by minimizing modal interactions, ensuring very low support-loss for both low and high TCF modes.

Implementation Method 1

a plurality of electrodes disposed around the periphery of the resonator assembly and configured to transduce information related to the first mode of operation and the second mode of operation

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The operation of the dual-mode resonator in the first mode of operation results in minimal vibration or movement at a plurality of first nodes and maximum vibration or movement at a plurality of first antinodes

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS20250309859A1Dual-mode MEMS resonators with low support loss

Publication Date: 2025.10.02 PANASONIC OF NORTH AMERICA

AI summary

A dual-mode resonator assembly includes a plurality of electrodes disposed around the resonator and configured to transduce information related to a first mode of operation of the dual-mode resonator assembly and a second mode of operation of the dual-mode resonator assembly. The plurality of electrodes includes electrodes associated with the first mode of operation and electrodes associated with the second mode of operation. The plurality of electrodes are disposed symmetrically and centered to nodes and antinodes of the first mode of operation and/or the second mode of operation. The electrodes are configured to also minimize feedback and noise from the first and second mode of operation.