Next Generation Applications Need Next Generation MEMS Gyro Technology

Environmental Robustness of Qualtré’s Gyroscopes
Qualtré’s highly differentiated and patented sensors and sensor intellectual property are based on disruptive, next generation Bulk Acoustic Wave (BAW) sensor design and High-Aspect Ratio combined Poly- and Single-crystal Silicon (HARPSS™) process innovations that transcend the capabilities of conventional inertial sensors. By combining high-frequency BAW resonant structures with the HARPSS fabrication process, Qualtré’s gyroscopes deliver a new level of price/performance and provide improved environmental tolerance and reliability, making our sensor technology extremely versatile to meet the demands of a broad range of applications.

Technology Evolution

Bulk-Acoustic Wave (BAW) Sensors

Unlike conventional tuning-fork gyroscopes, Qualtré’s BAW sensors utilize high-frequency degenerate modes to detect rotation-rate signals. This technology has the following inherent benefits:

  • Industrial grade bias instability (Low Drift)
    Accurate location-awareness and navigation.
  • Widest dynamic range
    Enables a wide range of detectable signals for many applications.
  • Best-in-class noise density
    Improves resolution for even more accurate measurements.
  • Exceptional immunity to shock and vibration
    Essential for automotive and industrial applications.
  • Scalable in size
    Can be optimized for the price/performance demands of specific applications.

conventional-vs-qualtre

Exceptional Immunity to Shock and Vibration

Typically the specifications for gyroscopes report accuracy data under pristine, “lab” conditions.  What is more important is how the gyroscope performs in the actual application under real world conditions — and, often, that means under shock and vibration.  With a fundamentally different design from conventional tuning-fork gyros, the BAW technology has strong inherent immunity to shock and vibration — this helps BAW gyros deliver real-world performance very comparable to that of “lab” conditions.
To illustrate this, the following graphic compares how the Allan Variance plots for a conventional tuning-fork gyro and Qualtré’s BAW gyro are affected by the introduction of random vibration.  Specifications will often only report the lower numbers in blue, which essentially represent the “best” specification for the gyroscope.  As seen below, the performance under random vibration drastically reduces the accuracy of the conventional gyro, while barely affecting the accuracy of the BAW gyro.  To learn more, please read the article: Evaluating error sources during MEMS gyroscope selection.

vibration

HARPSS™ Fabrication Process

At the core of Qualtré’s technology is the HARPSS fabrication process. Its unique features are what empower the unmatchable performance of BAW sensors. HARPSS capacitive nano-gaps (< 200 nm) provide extremely high electromechanical transduction, a key parameter in the implementation of highly sensitive, low-noise sensors.

groves

Qualtre’s HARPSS process enables the development of an entire family of MEMS devices.