Dual-Mode MEMS Resonator for Self-Temperature Frequency Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Microelectromechanical Systems (MEMS) resonators face challenges with temperature sensitivity, as silicon-based devices have a negative temperature coefficient of elasticity, leading to frequency deviations that are difficult to control, and the addition of external circuitry for temperature measurement consumes power and space while providing inaccurate measurements.
Innovation Solution
A dual-mode MEMS resonator operating in both in-plane and out-of-plane vibration modes, allowing for two frequencies to be generated within a single package, which can replace two separate resonators, and using these frequencies to determine temperature without external sensors, enabling more accurate temperature measurement and compensation for frequency drifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external circuitry is added to measure temperature, then temperature measurement capability is provided, but power consumption increases and space requirements increase while measurement accuracy remains insufficient
Solution Approach 1:
The MEMS resonator uses its own vibrational frequencies to sense temperature, eliminating the need for external temperature sensors. The resonator's natural response to temperature changes through frequency shifts provides self-diagnostic capability for temperature measurement
Solution Approach 2:
The same MEMS resonator structure serves dual purposes: generating timing frequencies and sensing temperature. By operating the resonator in multiple vibration modes, it simultaneously provides frequency reference and temperature measurement functions within a single device
2Measurement precision
If external circuitry is added to measure temperature, then temperature measurement capability is provided, but device area increases
Solution Approach 1:
The temperature sensing function is merged with the frequency generation function by using the same MEMS resonator structure. The resonator's vibrational modes provide both timing signals and temperature information, consolidating multiple functions into a single integrated device
Solution Approach 2:
The resonator measures temperature through its own frequency characteristics without requiring separate sensing elements. The device uses itself as the sensing element, eliminating the need for additional temperature sensor components and reducing overall device area
3Ease of manufacture
If silicon MEMS resonator is used, then integration and size are improved, but temperature sensitivity increases causing frequency deviations
Solution Approach 1:
The system uses the resonator's frequency shifts as feedback to determine temperature, which is then used to compensate for temperature-induced frequency deviations. This closed-loop approach maintains frequency stability despite temperature variations
Solution Approach 2:
The patent operates the resonator in multiple vibration modes with different temperature coefficients. By selecting and combining frequencies from modes with opposite temperature dependencies, the system compensates for temperature effects and maintains stable output frequency
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 power consumption and space requirements while providing more accurate temperature measurements and frequency stability, suitable for applications like GPS receivers, by using the dual frequencies to self-sense temperature and adjust frequencies accordingly.
Implementation Method 1
operating the MEMS resonator in an in-plane mode of vibration using a first oscillator, thereby obtaining a first electrical signal having a first frequency. concurrently operating the MEMS resonator in an out-of-plane mode of vibration using a second oscillator
Implementation Method 2
mixing the first and second electrical signals together, thereby obtaining a third electrical signal having a third frequency, the third frequency being proportional to a temperature of the MEMS resonator
Data Source
AI summary
A dual-output microelectromechanical system (MEMS) resonator can be operated selectively and concurrently in an in-plane mode of vibration and an out-of-plane mode of vibration to obtain, respectively, a first electrical signal having a first frequency and a second electrical signal having a second frequency that is less than the first frequency. The first and second electrical signals are mixed to obtain a third electrical signal having a third frequency, where the third frequency is proportional to a temperature of the MEMS resonator. The temperature is determined based on the third frequency. Values of the first and second frequencies can be adjusted based on the determined temperature to compensate for frequency deviations due to temperature deviations. Also described herein are methods and systems for determining the temperature of the dual-output MEMS and for performing frequency compensation, as well as a method of manufacturing the dual-output MEMS.