Toward ultimate performance in GHZ MEMS resonators: Low impedance and high Q

Harrington, Brandon P.; Shahmohammadi, Mohsen; Abdolvand, Reza

doi:10.1109/memsys.2010.5442310

Cited by 44 publications

(19 citation statements)

References 6 publications

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“…We have previously shown that multi-tethering of the Tpos resonators improves the q, Il, and power handling, while reducing the spurious modes, some of which could be very close to the target mode [22], [25], [26]. because the operation concept of the monolithic filters is similar to that of Tpos resonators, the same technique is adopted here.…”

Section: A Design Conceptmentioning

confidence: 99%

Low-loss lateral-extensional piezoelectric filters on ultrananocrystalline diamond

Fatemi

Abdolvand

2013

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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In this work, lateral-extensional thin-film piezoelectric- on-diamond (TPoD) filters with very low insertion loss (IL) values (<4 dB) are reported. Two different lateral-extensional modes of a resonant structure are coupled together to realize a two-pole filter. The filters of this work exhibit low IL values, with fractional bandwidth between 0.08% and 0.2%, and have a very small footprint. This paper reports on the lowest IL in the literature for lateral-extensional thin-film piezoelectric filters with 50 Ω terminations in the GSM frequency band (~900 MHz). The narrow-band filters of this work are fabricated on three ultrananocrystalline diamond substrates to achieve higher frequencies without excessive reduction in the feature size. The paper also thoroughly studies the parameters that affect the performance of such filters and then discussions are evaluated by the statistical data collected from the fabricated wafers.

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Section: A Design Conceptmentioning

confidence: 99%

Low-loss lateral-extensional piezoelectric filters on ultrananocrystalline diamond

Fatemi

Abdolvand

2013

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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“…With the advances in micromachining technologies, various types of MEMS resonators with a wide range of frequencies from tens of kHz to a few GHz with high quality factors have been demonstrated [1,2]. A variety of microscale electromechanical resonators have been considered/used in various applications such as sensitive and highly integrated chemical [3] and environmental sensors [4], filters [5] and gyroscopes [6].…”

Section: Introductionmentioning

confidence: 99%

Electrostatic frequency tuning of thermal piezoresistive MEMS resonators

Hajjam

Rahafrooz

Pourkamali

2012

2012 IEEE International Frequency Control Symposium Proceedings

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This paper presents a new technique for electrostatic tuning of the resonant frequency of in-plane thermal piezo-resistive micro-electromechanical resonators. The tuning method is based on applying a DC bias voltage between the underlying SOI handle layer and the suspended resonant structure. The DC bias voltage produces an electrostatic force which causes the bending of the resonant structure in the out of plane direction. The resulting stress in the structure causes a shift in its resonant frequency. The experiments were taken place under both atmospheric pressure and partial vacuum. Maximum upward and downward frequency shifts of +580ppm and -430ppm have been demonstrated. As a side product, due to minimized air damping, more than 2X resonator Q improvement was observed while tuning the resonator frequency. I. INTRODUCTIONWith the advances in micromachining technologies, various types of MEMS resonators with a wide range of frequencies from tens of kHz to a few GHz with high quality factors have been demonstrated [1,2]. A variety of microscale electromechanical resonators have been considered/used in various applications such as sensitive and highly integrated chemical [3] and environmental sensors [4], filters [5] and gyroscopes [6]. Arrays of such resonators can be batch fabricated at high quantities at a very low cost. The resonance frequency of silicon micromechanical resonators is dependent on the physical dimensions of the resonating structure. Process variations across the substrate (e.g. non-uniformities in photolithography, etching and film thickness) leading to variations and mismatch in the mechanical resonant frequencies are a major challenge for batch fabrication of micromechanical resonators. Postfabrication trimming is one of the ways to solve this issue. The post-fabrication frequency trimming methods make irreversible permanent changes to the frequency of the devices. Different frequency trimming techniques for MEMS silicon based micromechanical resonators have been presented. The techniques range from pulsed-laserdeposition/trimming [7], gold diffusion into the bulk of the resonator [8] and localized thermal oxidation [9].

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“…In order to effectively excite higher order harmonics in the resonant structure, the top electrodes are patterned to form interdigitated fingers. Also, a multi-tethering scheme can be used to improve spurious-mode suppression [11]. …”

Section: Introductionmentioning

confidence: 99%

High-frequency thin-film piezoelectric transformers

Fatemi

Abdolvand

2012

2012 IEEE International Frequency Control Symposium Proceedings

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A voltage step-up/impedance transformer is presented which operates by modifying the electrode configuration of lateral-extensional mode thin-film piezoelectric-on-substrate (TPoS) resonators. The individual electrode pairs that cover the stress concentration areas of a 10 th order harmonic 30MHz resonator are connected in series at the output port to effectively unbalance the input and output impedances. After inductive cancelation of the electrode/pad capacitances at the output port, a voltage gain of +10.4 dB is achieved in such transformers. Additionally, an impedance transformation ratio of 19:1 is obtained.

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Toward ultimate performance in GHZ MEMS resonators: Low impedance and high Q

Cited by 44 publications

References 6 publications

Low-loss lateral-extensional piezoelectric filters on ultrananocrystalline diamond

Low-loss lateral-extensional piezoelectric filters on ultrananocrystalline diamond

Electrostatic frequency tuning of thermal piezoresistive MEMS resonators

High-frequency thin-film piezoelectric transformers

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