Design of a Temperature-Stable RF MEM Capacitor

Nieminen, H.; Ermolov, Vladimir; Silanto, S.; Nybergh, K; Ryhänen, Tapani

doi:10.1109/jmems.2004.832192

Cited by 39 publications

(11 citation statements)

References 14 publications

(16 reference statements)

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“…Particularly noticeable are varactor diodes [6], paraelectric capacitors [7], and micro electromechanical system (MEMS) capacitors [8]. A specific characteristics of a varactor diode is its depletion region capacitance which can be varied by the applied bias voltage [9].…”

Section: State Of the Artmentioning

confidence: 99%

Wide piezoelectric tuning of ltcc bandpass filters

Alahmad

Mäenner

Matz

et al. 2005

IEEE MTT-S International Microwave Symposium Digest, 2005.

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This work treats design and fabrication issues associated with innovative tunable front-end components which combine two different ceramic technologies, namely multilayer ceramic circuit boards (low temperature cofired ceramics or LTCC) and piezoelectric actuator technology within a single device. The need for such components is particularly arising due to the increasing number of wireless services and associated frequency bands in the range between 0.5 and 2.5 GHz. This has led in the past to the concept of software-defined radio (SDR) which would provide a cost-efficient solution by treating signals digitally and software-controlled up to the highest possible frequencies and as close as possible towards the transmit antenna, while the final analogue section at the antenna comprises only few high-performing and frequencyagile, tunable components. However, as a consequence of demanding component specifications, SDR has not yet found noticeable application in consumer markets despite ongoing search for suitable device concepts and fabrication technologies.Similar to the known micro-electromechanical (MEMS) approaches for tuning and switching, this work presents a modified parallel plate capacitor with high-permittivity dielectric and piezoelectrically movable top electrode as a tuning element. Like in MEMS solutions, there is no tunable dielectric material required for tuning as for example paraelectric material, which would introduce additional losses. The proposed device therefore has the potential for a high quality factor. Contrasting MEMS, piezoelectric actuators exhibit proven reliability and lifetime. Also sticking of contact surfaces can be overcome by the actuator force. The size of the actuator in the order of several millimeters is not impedimental in the present context, since it compares well to the size of planar integrated filters in the frequency range mentioned.The vertical movement of the electrode opens an air gap above the dielectric film which allows for substantial lowering of the effective dielectric constant and capacitance. When applied as a shunt capacitor in a coupled microstrip lines LTCC bandpass filter, the center frequency of the filter is tuned from 1.1 GHz to 2.6 GHz (tunability of 135%) with 200 V control voltage and low insertion loss of value 4 dB (at zero-bias) to 2 dB (at the maximum bias). For a more compact size, one electrode of the piezoelectric element is simultaneously used as the center microstrip line of a filter employing three coupled lines. Its equivalent circuit has been used to explore the change of the capacitor parameters across the entire tuning range. The capacitor varied from 7 pF to 1.35 pF with a quality factor between 60 and 160. The quality factor could be improved by a factor of 7 when the metallization of the piezoelectric actuator, changes from 80 nm to 500 nm.This thesis discusses also the effects of tuning mechanism on the overall quality factor, return loss, insertion loss, and the relative bandwidth at the mid of the band as a function of ...

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Section: State Of the Artmentioning

confidence: 99%

Wide piezoelectric tuning of ltcc bandpass filters

Alahmad

Mäenner

Matz

et al. 2005

IEEE MTT-S International Microwave Symposium Digest, 2005.

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“…Some methods have been adopted to reduce the sensitivity to temperature, for example, using composite beam, optimising structure, and even employing new materials and so on. [3][4][5][6][7][8][9][10][11] All of these methods not only require advanced MEMS design efforts and special materials, but also have precise fabrication flow.…”

Section: Introductionmentioning

confidence: 99%

Design of DC-contact RF MEMS switch with temperature stability

Sun

Zhu

et al. 2015

AIP Advances

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Etching technique for ruthenium with a high etch rate and high selectivity using ozone gas In order to improve the temperature stability of DC-contact RF MEMS switch, a thermal buckle-beam structure is implemented. The stability of the switch pull-in voltage versus temperature is not only improved, but also the impact of stress and stress gradient on the drive voltage is suppressed. Test results show that the switch pull-in voltage is less sensitive to temperature between -20 • C and 100 • C. The variable rate of pull-in voltage to temperature is about -120 mV/ • C. The RF performance of the switch is stable, and the isolation is almost independent of temperature. After being annealed at 280 • C for 12 hours, our switch samples, which are suitable for packaging, have less than 1.5% change in the rate of pull-in voltage. C 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License. [http://dx Design of DC-contact RF MEMS switch with temperature stability

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“…Literature clearly state that damage mechanisms are basically depending on the plastic behavior of material (Rebeiz 2002), static rupture (Tabata 2008), fatigue (Espinosa 2006) and thermal fatigue (Nieminen 2004, Goldsmith 2005, fracture and creep (Rezvanian 2008), wear and electric failures (Reid 2003). Nevertheless, operation of the RF-microswitch may lead evenly to a collapse due to buckling (Shamshirsaz 2008) or to a dynamic resonance (Brusa and Munteanu 2006a;Brusa 2006c).…”

Section: Introductionmentioning

confidence: 99%

“…Interaction between electromechanical actions and environmental fluid surrounding the MEMS was evenly analysed (Veijola et al 2009). Only recently research activities were focused on the temperature role in microswitch functionality and reliability (Hasiang Pan 2002;Nieminen et al 2004;Zhu and Espinosa 2004;Goldsmith 2005;Kang 2005;Rezvanian 2008;Bognar 2009;Yan 2009;Mahameed 2010;Saeedivahdat 2010;Zamanian 2010). Unfortunately, conclusions and remarks are still in contrast each other.…”

Section: Introductionmentioning

confidence: 99%

Role of the electro-thermo-mechanical multiple coupling on the operation of RF-microswitch

Brusa

Munteanu

2012

Microsyst Technol

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A phenomenological approach is proposed to identify some effects occurring within the structure of the microswitch conceived for radio frequency application. This microsystem is operated via a nonlinear electromechanical action imposed by the applied voltage. Unfortunately, it can be affected by residual stress, due to the microfabrication process, therefore axial and flexural behaviors are strongly coupled. This coupling increases the actuation voltage required to achieve the so-called ''pull-in'' condition. Moreover, temperature may strongly affect strain and stress distributions, respectively. Environmental temperature, internal dissipation of material, thermo-elastic and Joule effects play different roles on the microswitch flexural displacement. Sometimes buckling phenomenon evenly occurs. Literature show that all those issues make difficult an effective computation of ''pull-in'' and ''pull-out'' voltages or evenly distinguishing the origin of some failures detected in operation. Analysis, numerical methods and experiments are applied to an industrial test case to investigate step by step the RF-microswitch operation. Multiple electro-thermomechanical coupling is first modeled to have a preliminary and comprehensive description of the microswitch behavior and of its reliability. ''Pull-in'' and ''pull-out'' tests are then performed to validate the proposed models and to find suitable criteria to design the RF-MEMS.

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Design of a Temperature-Stable RF MEM Capacitor

Cited by 39 publications

References 14 publications

Wide piezoelectric tuning of ltcc bandpass filters

Wide piezoelectric tuning of ltcc bandpass filters

Design of DC-contact RF MEMS switch with temperature stability

Role of the electro-thermo-mechanical multiple coupling on the operation of RF-microswitch

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