Series-resonant VHF micromechanical resonator reference oscillators

Lin, Yuqing; Lee, Seungbae; Li, Sheng-Shian; Xie, Yuan; Ren, Zeying; Nguyen, C.T.-C.

doi:10.1109/jssc.2004.837086

Cited by 252 publications

(45 citation statements)

References 22 publications

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“…However developing a MEMS resonator with high quality factor in MHz frequency ranges, which would be compatible with CMOS integrated circuits (Dragoi et al 2012) is very important in view of different applications. In integrated circuits, applications such as filters (Bannon et al 2000;Lopez et al 2009), timing and reference frequency devices (Lin et al 2004;Nguyen 2007), microprocessors (Abdelsalam et al 2010) and sensors such as pressure and humidity sensors (Shi et al 2013;Muniraj 2011) facing an important challenge either from scientific or engineering viewpoint that must be well addressed. As an important property, Quality factor (Q) is a scaled ratio between stored energy and damped energy per cycle, which is associated with frequency.…”

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confidence: 99%

Effects of slots on thermoelastic quality factor of a vertical beam MEMS resonator

Asadi

Sheikholeslami

2015

Microsyst Technol

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the resonance occurs in the mechanical domain. MEMS resonators have already started to use in various applications from wrist watches to the state of the art communications, due to their extremely features. However developing a MEMS resonator with high quality factor in MHz frequency ranges, which would be compatible with CMOS integrated circuits (Dragoi et al. 2012) is very important in view of different applications. In integrated circuits, applications such as filters (Bannon et al. 2000;Lopez et al. 2009), timing and reference frequency devices (Lin et al. 2004;Nguyen 2007), microprocessors (Abdelsalam et al. 2010) and sensors such as pressure and humidity sensors (Shi et al. 2013;Muniraj 2011) facing an important challenge either from scientific or engineering viewpoint that must be well addressed. As an important property, Quality factor (Q) is a scaled ratio between stored energy and damped energy per cycle, which is associated with frequency. In a MEMS resonator, Q is an indication of mechanical energy damping in the system that directly influences sensitivity and resolution of the device Hao et al. 2003). Theoretically, quality factor can be calculated for every frequency, whereas in practice, it is obtained for a specific resonance.In a beam type MEMS resonator, to understand and analyze the energy loss mechanisms, it is important to know the sources of energy loss. The latter could be consisted of support loss, thermoelastic loss and surface loss (Hao et al. 2003). Compression and decompression of an oscillating structure results an irreversible heat flow that is called thermoelastic damping (TED). In Clamped-Clamped (C-C) beam MEMS resonator, the beam in bending experiences a variation on temperature which causes a thermal gradient through the beam. The latter should be well adjusted to maintain the thermal equilibrium. To do this, energy must be intelligently dissipated while the quality factor of the Abstract Thermoelastic damping is one of the dominant mechanisms of structural damping in vacuum-operated microresonators. A three dimensional numerical model based on the finite element method is used for simulating thermoelastic damping in clamped-clamped microelectromechanical beam resonators. In this regards, both simple and slotted beam are considered. To understand the effect of slot positions and sizes on the resonator performance, resonant frequency and thermoelastic quality factor are calculated for both simple and slotted beams for a wide range of beam length from 10 to 400 µm. Punching slots in the resonator beam reduces the stiffness and mass of the beam which affect the resonant frequency. In addition thermomechanical coupling mechanisms of the resonator are affected by the slots which improve the thermoelastic quality factor. For most of the beam lengths, it is shown that the slots at the beam-anchor interface region, where the strain is high, are more effectively enhanced the thermoelastic quality factor than one at the centre of the beam region. However, the highest resonance frequency i...

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Effects of slots on thermoelastic quality factor of a vertical beam MEMS resonator

Asadi

Sheikholeslami

2015

Microsyst Technol

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“…R i and R o represent the non-idealities of the amplifier while C a represents the parasitic capacitances that exist across the resonator. In [3][4][5][6][7], the values of C a , R i , and R o were taken as zero as the resonator and amplifier were assumed to be ideal. Therefore, the analysis of the Transresistance oscillator in this paper is enhanced by including these components in the oscillator model.…”

Section: Transresistance Circuitmentioning

confidence: 99%

“…Equation (16) was presented in the previous studies [3][4][5][6][7] where the Transresistance oscillator was modeled using an ideal resonator with zero C a . However, (15) predicts a more accurate value for r m, crit as it takes into account the non-idealities of the resonator and amplifier.…”

Section: Circuit Theory Of Transresistance Oscillatormentioning

confidence: 99%

“…Although the Pierce oscillator has been the dominating topology in quartz watches, the Transresistance oscillator has become a popular choice among micromechanical oscillator designers as well. According to [2], most micromechanical oscillator designs [3][4][5][6][7] have used Transresistance amplifiers to provide sufficient gain for sustained oscillation while fewer designs [2] and [8] have adopted the Pierce topology. The large motional resistance of the micromechanical resonator is believed to have hindered the implementation and development of the micromechanical Pierce oscillator.…”

Section: Introductionmentioning

confidence: 99%

“…Most of these studies have focused on the Pierce circuit as it was the most widely used scheme in crystal oscillators for its excellent frequency stability. There are comparatively less study carried out on the Transresistance oscillator and the existing studies are based on ideal oscillator models [3][4][5][6][7]. The increasing use of the Transresistance topology in micromechanical oscillators calls for an in-depth study of its circuit properties and performance.…”

Section: Introductionmentioning

confidence: 99%

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Micromechanical oscillator circuits: theory and analysis

Wong

Palaniapan

2008

Analog Integr Circ Sig Process

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In this paper, detailed theoretical analysis of micromechanical Transresistance oscillator is presented. Analytical expressions are derived for the frequency pulling, critical transimpedance, maximum negative resistance, and start-up time constant of the Transresistance oscillator circuit which are useful for the design of micromechanical oscillators. These results are then used to study the frequency stability of Transresistance oscillator circuit and compare its operating conditions with that of the Pierce oscillator circuit which is widely used in micromechanical oscillators. The results conclusively show that the Transresistance oscillator has less start-up problems and better frequency stability than the Pierce oscillator. These results are then verified with a well-established circuit theory that compares the phase-frequency plots of the Pierce and Transresistance oscillator.

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The implementation of low-power and wide tuning range MEMS filters for communication applications

Goktas

Zaghloul

2016

Radio Sci.

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Theory and optimization were studied in detail to find optimum dimensions of fixed-fixed beam for the sake of low-power and wide-range frequency tuning applications. This optimization also provides a method to avoid device failure due to high thermal stress. The good agreement between theory, simulation, and measurement is achieved and can serve as a guidance for future works. Two resonators, consisting of multiple metal, dielectric, and polysilicon layers, were designed; the first resonator at 303.4 kHz and the second at 2053 kHz achieve the frequency tuning ranges of 35.7%-42.6%, respectively. A power consumption of 900 μW/beam is achieved for the first design of 152 μm length beam while providing a frequency tuning of 35.7%. Further increase in the tuning capability was achieved by the increase in the applied DC bias voltage between adjacent beams. GÖKTAŞ AND ZAGHLOUL MEMS FILTERS IMPLEMENTATION IN LOW POWER 1 PUBLICATIONS Citation: Göktaş, H., and M. E. Zaghloul (2016), The implementation of low-power and wide tuning range MEMS filters for communication applications, Radio Sci., 51,

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Series-resonant VHF micromechanical resonator reference oscillators

Cited by 252 publications

References 22 publications

Effects of slots on thermoelastic quality factor of a vertical beam MEMS resonator

Effects of slots on thermoelastic quality factor of a vertical beam MEMS resonator

Micromechanical oscillator circuits: theory and analysis

The implementation of low-power and wide tuning range MEMS filters for communication applications

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