Office of Technology Transfer – University of Michigan

Q-Control at RF Frequency in Micromechanical Mixer-Filters

Technology #2841

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Clark T.C. Nguyen
Managed By
Keith Hughes
Assistant Director, Physical Sciences & Engineering 734-764-9429


The uses of handheld wireless instruments have grown considerably in recent year, with demands for voice, image, and data all on one device. This increasing demand has been the catalyst for miniature technology development and the MEMS research field has responded strongly. Both highly selective filtering and low-loss low-noise mixing are important for the function of communication receivers and these functions can now be combined in micromechanical mixer filters (mixlers). If separated, performance can be maximized but limits are placed on size reduction and power consumption in portable communication devices.


Researchers at the University of Michigan have developed a new method for termination of micromechanical mixer-filters based on controlling the Quality factor (Q) of mechanical resonators via the feedback force generated by the RF current across the termination resistor (at RF frequency). This is an improvement compared to conventional termination methods based on IF feedback force (at resonance frequency) in that the value of the termination resistor is smaller by 10-100 times.

Applications and Advantages


  • Termination of micromechanical-nl-mixer-filters
  • Use in wireless communication-nl-systems


  • Required value of termination resistor is-nl-much smaller
  • Easier implementation of mechanical structure-nl-due to much lower frequency
  • Fixes conversion loss caused by-nl-RF current in earlier mixer filters