Frequency Tuning in Resonators

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Frequency Tuning in Micromachined Piezoelectric Lateral-Extensional Resonators Track Code    2011-004 Tags   engineering Posted Date    Apr 27, 2016 11:36 AM Researcher Reza Abdolvand Mohsen Ghahsareh Mohammad Modarres-Zadeh Background A MEMS resonator is small electromechanical device that vibrates at high frequencies. This device is integral in an array of applications such as signal filtering, timing references, mass sensing, biological sensing, and motion sensing. Specifically, thin-film piezoelectric MEMS resonators are designed for electronic oscillators and filters. Although piezoelectric resonators have many advantageous compared to the capacitive MEMS resonators, their frequency tuning is not as trivial. As a result, there is a need for tuning circuits that do not require external voltage for tuning operation and that are not as complicated as those used in phase locked loop (PLL) oscillators. According to the technology, the frequency tuning operation is implemented by causing the stiffness of the piezoelectric material to be dependent upon the impedance connected between the electrodes. Summary OSU researchers have demonstrated a method of tuning the frequency of an oscillator based on a micromachined piezoelectric lateral-extensional resonator using passive components. In a two-port bulk mode resonator, one port is utilized as tuning port by connecting variable resistance to it while the other port is connected to the drive signal. Varying the reactance at the output leads to a change in the voltage amplitude on port 2 resulting in a variable stress and consequently, variable equivalent stiffness. The change in stiffness causes a shift in the resonance frequency.  Potential Applications Microelectronic device industry Main Advantages Frequency tuning is achieved External voltage to the device is not needed Very simple scheme Stage of Development Proof of concept. Intellectual Property Patent Number           8350633B1      United States