Micromachined RF MEMS tunable capacitors using piezoelectric actuators

Park, J.Y.; Yee, Youngjoo; Nam, Hojung; Bu, Jong‐Uk

doi:10.1109/mwsym.2001.967330

Cited by 49 publications

(21 citation statements)

References 2 publications

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“…From (13), C T is tuned by the lateral movement (x). If we set the maximum lateral moving displacement as x max , the maximum capacitance (C max ) and minimum capacitance (C min ) as well as the capacitance tuning ratio can be calculated as…”

Section: E Tuning Ratio Of the Tunable Capacitormentioning

confidence: 99%

Signal Power-Insensitive Analog MEMS Tunable Capacitor by Immobilizing the Movable Plates

Yang

Han

Choi

et al. 2015

J. Microelectromech. Syst.

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This paper presents an extremely power-insensitive microelectromechanical systems (MEMS) tunable capacitor equipped with immobilization capability in the moving plates when an radio frequency signal is flowing. The proposed tunable capacitor is similar to the conventional metal-insulator-metal capacitor, but the top metal plate is capable of moving laterally as well as vertically; it moves to the left and right to set the capacitance value by modulating the overlap area between the top and bottom plates (analog tuning and high capacitance tuning ratio are the merits), and then the top plate is pulled down to be immobilized resulting in remarkable robustness to the signal power, as well as high capacitance value. The proposed tunable capacitor, which was fabricated by metal surface micromachining, showed the tuning ratio of 181% at 2 MHz (470-852 fF) and 194% at 1 GHz with lateral and vertical actuation voltages under 50 V. It also exhibited small capacitance change against the radio frequency (RF) signal power; the maximum capacitance variation by the signal power of up to 9 W was <5.5% over the full tuning range, which is the record-high power insensitivity among the analog MEMS tunable capacitors. This excellent power insensitivity is due to the immobilizing capability of the proposed tunable capacitor. The proposed tunable capacitor maintained the set capacitance value with a variation of <8% over 10 million cycles under 1-W signal (cold switching condition). The design, modeling, fabrication, and measurements, including RF characteristics, are all described in this paper.[ 2014-0345]Index Terms-Microelectromechanical system (MEMS), tunable capacitor, power insensitivity, two-axis actuation, metal-insulator-metal (MIM) capacitor.

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Section: E Tuning Ratio Of the Tunable Capacitormentioning

confidence: 99%

Signal Power-Insensitive Analog MEMS Tunable Capacitor by Immobilizing the Movable Plates

Yang

Han

Choi

et al. 2015

J. Microelectromech. Syst.

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“…During this period (mid-1990s), there were three dominant classes of MEMS approaches for actuation: electrostatic [23], piezoelectric [48], and thermal [24]. Electrostatic approaches usually involve high-voltage (but low-amperage) actuation, which complicate implementation in traditional CMOS circuitry.…”

Section: ) Switch Researchmentioning

confidence: 99%

Field-Programmable Wiring Systems

et al. 2015

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This paper discusses concepts of adaptive wiring manifolds, in which soft-configured wires can be formed ''on demand'' to form dedicated conductive pathways that can connect many points within an embedded system. ABSTRACT | Field-programmable wiring systems refer to methods and hardware that can maintain the interconnection of components of different types. Generally, field-programmable wiring systems support the use of multidomain fabrics that can be used to route analog, power, digital signals, optical, microwave signals, etc. This paper reviews fundamental concepts associated with the practical implementation of fieldprogrammable wiring systems. The paper also provides different implementation examples and discusses a list of challenges and recommendations for future work in this area.

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“…A MEMS capacitor has been fabricated in a thin film technology using a dual gap relay type design by Rijks et al, [33], the capacitor shows a continuous and reversible capacitance tuning with a tuning ratio up to 17 ( the capacitance tuned roughly from 0.9 pF to 0.05 pF), while requiring an actuation voltage of only 20 V. A quality factor of 150 to 500 has been measured in the frequency range of 1 to 6 GHz. Park et al, [34], fabricated a micromachined RF MEMS tunable capacitor using piezoelectric actuator. The fabricated device has a tuning ratio of 3.1 to 1 at bias voltage of 6 V and a quality factor of 210 at 1 GHz.…”

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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Micromachined RF MEMS tunable capacitors using piezoelectric actuators

Cited by 49 publications

References 2 publications

Signal Power-Insensitive Analog MEMS Tunable Capacitor by Immobilizing the Movable Plates

Signal Power-Insensitive Analog MEMS Tunable Capacitor by Immobilizing the Movable Plates

Field-Programmable Wiring Systems

Wide piezoelectric tuning of ltcc bandpass filters

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