Unreleased Coupled MEMS Resonators and Transmission Filters

Technology #17157

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Inventors
Professor Dana Weinstein
Department of Electrical Engineering and Computer Science, MIT
External Link (engineering.mit.edu)
Wentao Wang
Department of Mechanical Engineering, MIT
Ashwin Seshia
Department of Engineering, University of Cambridge
Andreja Erbes
Department of Engineering, University of Cambridge
Managed By
Christopher Noble
MIT Technology Licensing Officer - Clean and Renewable Energy
Patent Protection

UNRELEASED COUPLED MEMS RESONATORS AND TRANSMISSION FILTERS

US Patent Pending US 2017-0012338

Application

This technology can be applied to electronic systems that require low phase-noise oscillators and high-performance transmission filters, such as mm-wave communication, high speed digital circuits, and navigation systems.

Problem Addressed

Electronic manufacturers currently use Thin-Film Bulk Acoustic Wave Resonators (FBAR) and/or Surface Acoustic Wave (SAW) resonators to manufacture Micro-electro-mechanical systems (MEMS). However, existing MEMS devices require separate manufacturing of the resonator and the circuit-board upon which the resonator is mounted. There are current techniques that allow for the direct integration of MEMS devices with the complementary integrated circuits; however, the resonators still require a release-step in order to create fully suspended moving structures. Not only does this integration technique add complexity to the manufacturing of MEMS devices, but the manufacturing process also reduces circuit performance. 

Technology

This technology removes the need for post-processing release steps by creating Acoustic Bragg Grating Coupler (ABGC) structures that allow vibration energy to flow between distinct cavities. The acoustically coupled multi-cavity structures allow the resonator to take advantage of a phenomenon called Mode Localization, where vibration energy is spatially localized. This configuration improves the mechanical quality by reducing energy leakage. It also improves motional resistance by increasing the vibration amplitudes, and consequently the generated motional currents. Moreover, this technology also proposes the use of a multi-cavity structure for the design of electronic transmission filters. The use of acoustically coupled resonator cavities makes the manufacture of two types of transmission filters possible: Transmission Line and a Multi-pole topology. Altering the coupling strength between the cavities allows for the design of transmission filters with adjustable properties, such as the bandwidth of pass-band and the central frequency. 

Advantages

  • No need for post-processing surface mounting steps
  • Low-cost
  • Tunable-shape factors
  • Low Power Consumption
  • Small footprint