Dual-Output MEMS Resonator Using Mode Mixing for Temperature Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Microelectromechanical Systems (MEMS) resonators face challenges in temperature sensitivity, with silicon resonators having a negative temperature coefficient of elasticity that leads to frequency deviations, making it difficult to control temperature and maintain stable frequencies, especially in modern handheld devices where size, power consumption, and CMOS compatibility are critical.
Innovation Solution
A dual-mode MEMS resonator operating in both in-plane and out-of-plane vibration modes, allowing for two distinct frequencies to be generated within a single package, which can be used to determine temperature without external sensors, enabling accurate temperature compensation and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external temperature sensors and circuitry are added to measure temperature for compensation, then temperature measurement accuracy improves, but power consumption increases and device space requirements increase
Solution Approach 1:
The resonator device performs multiple functions: it generates frequency output and simultaneously measures temperature through its dual vibration modes. The first vibration mode provides frequency reference while the second mode provides temperature sensing capability, eliminating the need for separate temperature sensors and reducing overall power consumption.
Solution Approach 2:
The patent combines temperature sensing and frequency reference functions into a single resonator device. By utilizing two different vibration modes of the same resonator structure, the system merges what would traditionally require separate components (frequency oscillator and temperature sensor) into one integrated device.
2Measurement precision
If external temperature sensors and circuitry are added to measure temperature for compensation, then temperature measurement accuracy improves, but device complexity and space requirements increase
Solution Approach 1:
The resonator device performs multiple functions: it generates frequency output and simultaneously measures temperature through its dual vibration modes. The first vibration mode provides frequency reference while the second mode provides temperature sensing capability, eliminating the need for separate temperature sensors and reducing overall power consumption.
Solution Approach 2:
The patent combines temperature sensing and frequency reference functions into a single resonator device. By utilizing two different vibration modes of the same resonator structure, the system merges what would traditionally require separate components (frequency oscillator and temperature sensor) into one integrated device.
3Ease of manufacture
If silicon resonators are used, then CMOS compatibility and integration improve, but temperature sensitivity increases due to negative temperature coefficient of elasticity
Solution Approach 1:
The system uses feedback to compensate for temperature effects. The second vibration mode provides temperature information that is used to adjust or compensate the frequency output from the first vibration mode, maintaining frequency stability despite temperature variations inherent in silicon resonators.
Solution Approach 2:
The patent exploits changes in vibration frequency parameters with temperature. By monitoring how the frequency of the second mode changes with temperature, the system can compensate for temperature-induced frequency drift in the first mode, maintaining reliable frequency output.
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 dual-mode MEMS resonator provides more accurate temperature measurements and stable frequency output, reducing the need for external temperature sensors and power consumption, while also offering a compact solution for applications like GPS receivers.
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
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
There is provided a dual-output microelectromechanical system (MEMS) resonator. The 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 being 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. There is also provided methods and systems for determining the temperature of the dual-output MEMS, for compensating the frequency, and a method of manufacturing the dual-output MEMS.