An array of square plate resonators with adjustable resonance frequency

Download
2022-8-19
Polat, Halim
In this study, a MEMS square plate resonator with adjustable resonance frequency is designed, mathematically modelled and verified with finite element analysis (FEA) and experiments. Resonance frequency of microelectromechanical system (MEMS) square plate is adjusted with the help of several cutouts which are placed in unique lines like center lines and nodal lines. First of all, plates are modelled with the help of semi-analytic method called Rayleigh-Ritz method for the 1st and 2nd modes since higher modes have higher resonance frequencies. Later, effects of cutouts are included with subtracting kinetic and strain energies of cutouts from those of the plate. Up to 140 Hz frequency shift is proved to be achievable with simply changing position of cutouts. Electrostatic spring softening is calculated and added to general formula. Lastly, thermal effects are considered to have impact on modulus of elasticity, volume and density of the plate. Thermal effects are included in the formula with the help of thermal coefficient of expansion and temperature sensitivity is calculated to 2 Hz/˚C. Analytical model is verified with finite element modelling (FEM) at the end of the second chapter. Several finite element analyses (FEA) including eigenfrequency and thermal modules were done to prove validity. MEMS plates are manufactured by METU MEMS CENTER, which utilizes silicon on insulator (SOI) wafers. A basic test setup with network analyzer, vacuum chamber and power supplies is prepared to test manufactured MEMS plates to observe resonance frequency shift of the plates with cutouts. Quality factors over 9000 with a resonance frequency of 78.6 kHz is shown. With a measured temperature sensitivity of 3.8 Hz/˚C is achieved, proving that these microplate resonators are feasible temperature sensors.

Suggestions

A Novel Characterization Method for MEMS Based Electrostatic Resonators for Q Enhancement and Feedthrough Current Elimination
AYDIN GÖL, EBRU; Kangul, M.; Gökce, Fuat; Zorlu, O.; Külah, Haluk (2016-11-03)
This paper introduces a new technique for electrostatic resonance characterization based on 2nd harmonic distortion terms at the output current. Mathematical analysis of the output current shows that the 2nd harmonic component exhibits higher quality factor (Q) than the 1st harmonic. Besides, output current to feedthrough current ratio is higher in the 2nd harmonic term. Experimental results show that the Q of the resonating system is enhanced by 66% with 2nd harmonic operation. Moreover, the resonance peak...
A PARYLENE BONDING BASED FABRICATION METHOD FOR GRAVIMETRIC RESONANT BASED MASS SENSORS
Gokce, Furkan; Aydın, Eren; Kangül, Mustafa; Toral, Taylan B.; Zorlu, Ozge; Sardan-Sukas, Ozlem; Külah, Haluk (2017-06-22)
In this study, a fabrication method utilizing parylene bonding for gravimetric resonant based mass sensors is presented. First, parylene bonding was experimentally tested and compared with the literature. Average shear strength was measured as 16.3 MPa (sigma=3MPa). Then, resonators located on top of a microchannel for real-time detection were fabricated using the presented method. Simulations and experiments verify proper operation of the fabricated resonators, and the applicability of the method for fabri...
A laterally resonating gravimetric sensor with uniform mass sensitivity and high linearity
Eroglu, D.; Bayraktar, E.; Külah, Haluk (2011-09-01)
In this paper, a laterally resonating gravimetric sensor with high linearity and uniform mass sensitivity is presented for biochemical sensor applications including rare-cell detection. The sensor utilizes symmetrically placed, balanced, folded spring beam structures to ensure lateral motion of the proof mass and limit the displacement difference between the proof mass center and edges. The dynamic mass sensitivity range of the resonator is increased by using the above mentioned properties of the resonators...
A Lorentz force MEMS magnetometer
Pala, Sedat; Cicek, Meltem; Azgın, Kıvanç (2016-11-03)
This paper presents a Lorentz force magnetometer with a MEMS resonator structure as a sensor. Magnetometer composed of a resonator and a grill structure. The grill structure reduces the heat generation due to the current required to generate the Lorentz force. The proposed sensor is produced with standard SOI micromachining processes with device layer thickness of 35 mu m. The natural frequency of resonator is around 83 kHz, Q-factor of 1870 at around 40 mTorr ambient pressure. Tests are done for 1.12 mT ma...
A Modular Superconducting Generator for Offshore Wind Turbines
Keysan, Ozan; Mueller, Markus A (2013-05-01)
In this study, a new claw-pole type transverse flux superconducting generator topology is presented. The machine has a stationary superconducting field winding, which eliminates electrical brushes and cryocouplers. The machine is specifically designed for low-speed high torque applications such as large offshore wind turbines. The proposed machine is robust and has a modular structure.
Citation Formats
H. Polat, “An array of square plate resonators with adjustable resonance frequency,” M.S. - Master of Science, Middle East Technical University, 2022.