mems在射頻無線通訊上的應用 -...

13
6 MEMS 在射頻無線通訊上的應用 ■國立清華大學/李昇憲 近年來微機電技術應用在射頻領域的研究與發展正方興未艾,主要的推進力來自於人們 對於無線通訊與行動電子裝置的殷切需求,射頻微機電(RF-MEMS)技術正扮演著協助人們追 求理想生活的關鍵角色。本文將介紹射頻微機電元件對於無線通訊架構的重要性,並概述射 頻微機電的歷史沿革與發展,同時展示筆者所屬團隊目前最新的研究成果與其未來的發展 性,以期鼓勵國內有志於從事微機電領域的產學尖兵,能夠投入這塊極具發展潛力的產業。 一、前言 射頻微機電(RF-MEMS) 技術主要是利 IC 相容的半導體製程或微機電製程來開 發應用於射頻領域的微型元件,包含微機械 共振器(Resonator)、振盪器(Oscillator)、濾 波器(Filter) 、混頻器(Mixer) 、微機械開關 (Switch)、微型天線(Antenna)、可變電容與 電感等元件;對照於傳統的電晶體電路,射 頻微機電元件通常具有高 Q 值、低損耗、 高阻絕性、高線性度與優異的功率負載能 力。半導體與積體電路近半世紀來蓬勃發 展,取代或抑制了大部分體積較大但性能較 佳的機械電路,例如純機械式開關或壓電陶 瓷濾波器等;但也因為 IC 製造技術的豐沛 資源,微機電製造技術也漸漸能夠製造微米 級、甚至奈米級的微型可動元件,因此足以 提供高性能、低成本、高集成性(Integration) 與媲美 IC 晶圓級大量製造特性的微機械電 路,重新找回利用機械原理操作的優勢。筆 者認為台灣正處於成熟 IC 技術與新興 MEMS 產業這樣一個絕佳的立足點,我們 的研發人員不僅須具備電子電路的背景,更 要追求其他領域的知識,才能適應甚至創造 ﹝圖 1﹞手機內部實體說明及其簡略功能架構圖。 陰影部份表示離散式元件,其餘部分由積體電路 單晶片 IC 實現。 未來各項領域高度整合的產業(Interdisciplinary Fields) 行動通訊可說是目前微機電系統最具 能量的市場,其未來需求將遠高於資訊週邊 及汽車產品,筆者在文中主要探討射頻微機 電元件在手機無線收發前端模組的應用與 其未來的影響力,並逐一介紹各式微機械共 振器與其相關的微機械電路,最後以筆者在 射頻微機電領域數年的經驗來探討如何以 台灣現有半導體工業的優勢發展屬於我們 自己的 RF-MEMS 產業。

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  • 6

    MEMS

    /

    (RF-MEMS)

    (RF-MEMS) IC

    (Resonator)(Oscillator)(Filter)(Mixer)(Switch)(Antenna)

    Q

    IC

    (Integration) IC

    IC MEMS

    1

    IC

    (Interdisciplinary Fields)

    RF-MEMS

  • 7

    Q (High-Q Passives) 1 (Discrete Components)

    (Wireless Transceivers) Q

    ()

    (RF) (IF) (Frequency Selection) (Frequency Generation)(Timing Reference) Q (Discrete)(Ceramic Filters)(SAW Filters)(Quartz Crystals)FBAR (Film Bulk Acoustic Resonator Filters)(Interface Circuits)(Packaging)(Assembling)

    Superheterodyne [1] 2 (a)( Q )

    I

    Q

    IQOsc.

    QuartzXstal

    IFAmp

    SAWIF FilterMixer

    SAWRF Filter

    90

    QuartzXstal

    VCO

    ChannelSelect PLL

    LNACeramicRF Filter

    Antenna

    Tunable Off-ChipLC Tank

    Off-ChipComponent

    I

    Q

    IQOsc.

    QuartzXstal

    IFAmp

    SAWIF FilterMixer

    SAWRF Filter

    90

    QuartzXstal

    VCO

    ChannelSelect PLL

    LNACeramicRF Filter

    Antenna

    Tunable Off-ChipLC Tank

    Off-ChipComponent

    (a)

    Off-ChipComponent

    Rx Out Q

    FrequencySynthesizer

    LNA

    Antenna

    AGC

    LPF

    LPF

    Rx Out I

    MixerSAW

    RF Filter

    LowpassFilter

    LowpassFilter

    2

    Amp

    2

    0 90

    0 90

    0 90

    Amp

    MixerLNASAW

    RF FilterSwitch Amp AGC Amp

    QuartzXstal

    Off-ChipComponent

    Rx Out Q

    FrequencySynthesizer

    LNA

    Antenna

    AGC

    LPF

    LPF

    Rx Out I

    MixerSAW

    RF Filter

    LowpassFilter

    LowpassFilter

    2

    Amp

    2

    0 90

    0 90

    0 90

    Amp

    MixerLNASAW

    RF FilterSwitch Amp AGC Amp

    QuartzXstal

    (b)

    (N+1)/N

    Duplexer

    RF BPF

    RF BPF

    RF BPF

    Duplexer

    Duplexer

    LNA RF BPFFrom TX

    LNA

    LNA

    LNA

    LNA

    LNA

    From TX

    From TX

    RF BPF

    0

    090

    90

    I

    QI

    Q

    RF BPF

    GSM 900

    PCS 1900

    DCS 1800

    AntennaCDMA

    WCDMA

    CDMA-2000 Tank

    RXRF Channel Select PLL

    RXRF LOXstalOsc

    AGC

    AGC

    A/D I

    A/D Q

    (N+1)/N

    Duplexer

    RF BPF

    RF BPF

    RF BPF

    Duplexer

    Duplexer

    LNA RF BPFFrom TX

    LNA

    LNA

    LNA

    LNA

    LNA

    From TX

    From TX

    RF BPF

    0

    090

    90

    I

    QI

    Q

    RF BPF

    GSM 900

    PCS 1900

    DCS 1800

    AntennaCDMA

    WCDMA

    CDMA-2000 TankTank

    RXRF Channel Select PLL

    RXRF LOXstalOsc

    AGC

    AGC

    A/D I

    A/D Q

    (c)

    2

    (a)(Superheterodyne Architecture)

    (b)(Direct-Conversion Architecture)

    (c)(Multi-Mode Multi-Band

    Wireless Systems)

  • 8

    Q

    (Off-Chip Components) (Direct-Conversion Receiver Architectures) [2](IF Filters) 2 (b) (Integrated Inductor Technologies) [3](Bias)(Matching Networks)(Off-Chip Inductors)

    (Robustness)(Power Efficiency)

    (Multi-Mode/Standard Reconfigurable Handsets) 2(c)(RF Front-End Filters)

    3GPP (the 3rd Generation Partnership Project) WiMAX 50 ()(> 50)

    I

    Q

    IQOsc.

    Mech.Res.

    IFAmp

    90

    Antenna

    Switchable Mech.

    Mech.Mixer-Filter

    Res. Oscillator

    On-ChipMech. Circuit

    Multi-Band ProgrammableChannel-Select Filter Bank

    SeriesSwitch

    I

    Q

    IQOsc.

    Mech.Res.

    IFAmp

    90

    Antenna

    Switchable Mech.

    Mech.Mixer-Filter

    Res. Oscillator

    On-ChipMech. Circuit

    On-ChipMech. Circuit

    Multi-Band ProgrammableChannel-Select Filter Bank

    SeriesSwitch

    3

    Q

    (Miniaturization)(Integration)

    TI DMD (Digital Micromirror Device) Analog Devices Inc. (ADI)Avago FBAR

  • 9

    (Ultra-Low Power)(High Selectivity) (Bandpass Filters) (Reference Oscillators)(Mixer-Filters)(MEMS Switches)

    (Miniaturized)(Integrated)(Low Power)(Robustness)

    (Bulky)(Discrete) Q (Direct-Conversion)[2] IF (Wideband IF)[4]

    Q Superheterodyne [1]

    [5]

    3 [5]

    (1) (RF Channel

    Selection) 3

    Q (Filter Banks)()

    (ADC) (Baseband Components) Q

    Q (Q 10,000)

    (2)(All-Mechanical Signal Processing) 3 Q

    (Mixing) (Antenna Switching)(Phase-Shifting)(Charge Pumping)(Frequency Generation) (A/D Conversion)

  • 10

    (3)(Low

    Power Micro-Mechanical Frequency Synthesizer (Local Oscillator)) 3 (Local Oscillator) Q

    (Phase-Locked Loops)

    (Power Saving)

    (Selectivity or Q)

    Q 3 Q

    Q (Quartz Crystals)(Surface Acoustic Wave Devices) Q 1,000

    ( )

    CMOS MEMS ()(kHz GHz)(Frequency Selection)(Frequency Generation)

    CAD-Layout ()

    (Multi-Mode Multi-Standard)

    1 Q

    (Comb Drive Actuator)[6] 1 Q 80,000()

    LF (30kHz - 300kHz)MF(300kHz - 3MHz)

    (Clamped-Clamped Beam)[7] 1 (Vertical Vibration)

    10MHzQ 8,000 Squeeze Film Damping Q 100

  • 11

    1 Q

    1.

    [6]

    Frequency (Hz)

    Tran

    smis

    sion

    (dB

    )

    fo=18.8kHzQ=51,000

    Frequency (Hz)

    Tran

    smis

    sion

    (dB

    )

    fo=18.8kHzQ=51,000

    Q~53,000 @ 18.8kHz () Q~100 @ 18.8kHz () Q Flexural (LF-MF) Rx ~1M-5M

    2.

    [7]

    Tran

    smis

    sion

    (dB

    )

    Frequency (MHz)

    Tran

    smis

    sion

    (dB

    )

    Frequency (MHz)

    Q~8,000 @ 10MHz () Q~50 @ 10MHz () Q~300 @ 70MHz (anchor loss) Q Flexural (HF-VHF) Rx ~500-5,000

    3.

    [8]

    fo=101 .3M HzQ=11,500

    fo=101 .3M HzQ=11,500

    Q~11,500@ 10-200MHz () Q~2,000 @ 90MHz () Q Flexural (VHF) Rx ~500-5,000

    4.

    [9]

    -90-80

    -70

    -60

    -50

    -40

    -30

    -20

    61.08 61.13 61.18 61.23 61.28 61.33

    Tran

    smis

    sion

    (dB

    )

    Frequency (MHz)

    Q= 48,000Rx = 1.5 k

    -90

    -80

    -70

    -60

    -50

    -40

    -30

    -20

    61.08 61.13 61.18 61.23 61.28 61.33

    Tran

    smis

    sion

    (dB

    )

    Frequency (MHz)

    Q= 48,000Rx = 1.5 k

    Q~48,000@ 61MHz () Q~10,000 @ 61MHz () Q Extensional (VHF) Rx ~500-5,000

    5. C

    onto

    ur

    [11]

    -102

    -96

    -90

    -84

    1507.4 1507.8 1508.2Frequency

    Pow

    er (d

    Bm

    )

    fo=1.51GHzQ=11,555

    -102

    -96

    -90

    -84

    1507.4 1507.8 1508.2Frequency

    Pow

    er (d

    Bm

    )

    Frequency

    Pow

    er (d

    Bm

    )

    fo=1.51GHzQ=11,555

    Q~11,555 @ 1.5GHz () Q~10,100 @ 1.5GHz () Q Q Extensional (VHF-UHF) Rx ~500-50,000

    6.

    [12]

    Q~2,300 @ 1.47GHz () Q>2,000 @ 1.47GHz () 1GHzQ Extensional (VHF-UHF) Rx ~500-50,000

    7. C

    onto

    ur

    [13]

    1 463 .4 146 3.6 1 463 .8 1464 1 464 .2-9 8-9 6

    -9 4

    -9 2

    -9 0

    -8 8

    fo=1.464GHz

    Q=15,248

    Pow

    er [d

    Bm

    ]

    Frequency [MHz]1 463 .4 146 3.6 1 463 .8 1464 1 464 .2-9 8

    -9 6

    -9 4

    -9 2

    -9 0

    -8 8

    fo=1.464GHz

    Q=15,248

    Pow

    er [d

    Bm

    ]

    Frequency [MHz]

    Q~15,248 @ 1.46GHz () Q~10,165 @ 1.46GHz () 1GHzQ Extensional (VHF-UHF) Rx ~500-50,000

  • 12

    HF (3MHz - 30MHz)Anchor Loss

    (Anchor)(Substrate) Q VHF (30MHz-300MHz) Anchor Loss VHF Q (Nodal Support)(Free-Free Beam)[8] 1

    Anchor VHF Q 10,000

    (Flexural Mode) k (Equivalent Stiffness)

    mkfo 2= m

    UHF (300MHz - 3GHz)

    Extensional Mode 1

    (Wine-Glass Mode)[9]61MHz Q 200,000 Q (Polysilicon) Q Contour-Mode

    100MHz- 1.8GHz 1GHz Anchor Anchor Loss Q 1,600 [10]()[11]

    Q Q 10,000 Squeeze Film Damping

    UHF ()(Transduction Area)(Motional Current)(50) (Ring Resonators) 1

    Contour-Mode [13]

    (Quarter Wavelength)

    1.464-GHz Q 15,000 MEMS CMOS

    2

  • 13

    (Spurious Modes)

    (Mechanical Coupling) 2 ( N )

    N N [14] Q 125k() 15k(

    ) 2 (Flexural-Mode)[15] 480

    2 [16] 11.73k 2.56kQ 100,000

    Q Q

    N

    (Transmitter)

    2

    1.

    [1

    4]

    Rx=125k@ 15.4MHz (1 Res.) Rx=43k@ 15.2MHz (3 Res.) Rx=22k@ 15.4MHz (10 Res.) Rx=15k@ 15.4MHz (20 Res.) Flexural (HF) Q~3,800-6,800

    2.

    [1

    5]

    0

    50

    100

    150

    200

    250

    300

    69.50 70.00 70.50 71.00 71.50

    Frequency [MHz]

    Out

    put [

    uA]

    Rx = 480Rx = 480

    1Res.3Res.

    5Res.

    7Res.

    0

    50

    100

    150

    200

    250

    300

    69.50 70.00 70.50 71.00 71.50

    Frequency [MHz]

    Out

    put [

    uA]

    Rx = 480Rx = 480

    1Res.3Res.

    5Res.

    7Res.

    Rx=2.82k@ 71.7MHz (1 Res.) Rx=2.3k@ 70.1MHz (3 Res.) Rx=1k@ 69.7MHz (5 Res.) Rx=0.48k@ 69.6MHz (7 Res.) Flexural (VHF) Q~9,100-17,500

    3.

    [1

    6]

    -110-100

    -90

    -80-70-60-50

    -40-30

    61.73 61.78 61.83 61.88 61.93

    Tran

    smis

    sion

    (dB

    )

    Frequency (MHz)

    1Res.3Res.5Res.

    9Res.

    -110-100

    -90

    -80-70-60-50

    -40-30

    61.73 61.78 61.83 61.88 61.93

    Tran

    smis

    sion

    (dB

    )

    Frequency (MHz)

    1Res.3Res.5Res.

    9Res.

    Rx=11.73k@ 61.8MHz (1 Res.) Rx=6.34k@ 61.8MHz (3 Res.) Rx=4.04k@ 61.8MHz (5 Res.) Rx=2.56k@ 61.8MHz (9 Res.) Extensional (VHF) Q~118,900-161,000

  • 14

    Q

    (Insertion Loss)(Phase Noise)

    3

    [17]

    [7] Q

    3 9-MHz [18]

    ( Loss Pole)

    (Transfer Function)

    3 [19][20]

    (Single-Ended System) Feedthrough Feedthrough

    Feedthrough (Differential)

    [21] 3 (Resonator Array)(Fully-Differential)

    (Parasitics) Feedthrough

    3 [22]

    (Programmable Channels and Bandwidths)() (Low Impedance)(Low Insertion Loss)(Forth-Order)(Differential-Mode Input) (Common-Mode Output)(Eighth-Order)(Filter Transfer Function)

  • 15

    3

    1.

    [

    17]

    340kHz 403Hz 0.09% 64dB < 0.6dB

    2.

    [

    7]

    7.81MHz 18kHz 0.23% 35dB < 2dB

    3.

    [18

    ]

    -70

    -60

    -50

    -40

    -30

    -20

    -10

    0

    8.69 8.74 8.79 8.84 8.89

    Tran

    smis

    sion

    (dB

    )

    Frequency (MHz)

    -70

    -60

    -50

    -40

    -30

    -20

    -10

    0

    8.69 8.74 8.79 8.84 8.89

    Tran

    smis

    sion

    (dB

    )

    Frequency (MHz)

    9MHz 20kHz 0.2% 51dB < 2.8dB

    4.

    [19]

    -21

    -18

    -15

    -12

    -9

    -6

    -3

    0

    67.70 67.88 68.05 68.23 68.40

    Frequency [MHz]

    Tran

    smis

    sion

    [dB

    ]Tr

    ansm

    issi

    on (d

    B)

    Frequency (MHz)

    -21

    -18

    -15

    -12

    -9

    -6

    -3

    0

    67.70 67.88 68.05 68.23 68.40

    Frequency [MHz]

    Tran

    smis

    sion

    [dB

    ]Tr

    ansm

    issi

    on (d

    B)

    Frequency (MHz)

    68.1MHz 190kHz 0.28% > 10dB < 2.7dB

    5. C

    onto

    ur

    [20]

    -25

    -20

    -15

    -10

    -5

    0

    155.2 155.4 155.6 155.8 156.0 156.2 156.4

    Tran

    smis

    sion

    (dB

    )

    Frequency (MHz)

    -25

    -20

    -15

    -10

    -5

    0

    155.2 155.4 155.6 155.8 156.0 156.2 156.4

    Tran

    smis

    sion

    (dB

    )

    Frequency (MHz)

    155.9MHz 201kHz 0.13% 20dB 2.5dB

    6.

    [21]

    -75-70-65-60-55-50-45-40-35-30-25-20-15-10-50

    162.6 162.8 163.0 163.2 163.4 163.6

    Tran

    smis

    sion

    (dB

    )

    Frequency (MHz)

    Terminated

    Un-Term.

    -75-70-65-60-55-50-45-40-35-30-25-20-15-10-50

    162.6 162.8 163.0 163.2 163.4 163.6

    Tran

    smis

    sion

    (dB

    )

    Frequency (MHz)

    -75-70-65-60-55-50-45-40-35-30-25-20-15-10-50

    162.6 162.8 163.0 163.2 163.4 163.6

    Tran

    smis

    sion

    (dB

    )

    Frequency (MHz)

    Terminated

    Un-Term.

    163.1MHz 98.5kHz 0.06% > 20dB 2.43dB

    7.

    [22]

    -80

    -70

    -60

    -50

    -40

    -30

    -20

    -10

    0

    161.8 162.8 163.8 164.8

    Un-terminatedTerminated

    Tran

    smis

    sion

    (dB

    )

    Frequency (MHz)

    Terminated

    Un-Term.

    -80

    -70

    -60

    -50

    -40

    -30

    -20

    -10

    0

    161.8 162.8 163.8 164.8

    Un-terminatedTerminated

    Tran

    smis

    sion

    (dB

    )

    Frequency (MHz)

    Terminated

    Un-Term.

    163.3MHz 253.7kHz 0.16% > 20dB < 2.73dB

  • 16

    3()

    8.

    [

    14]

    TIAvo-

    vo+

    RoRi

    CBRx CxLx

    CoCo1 Co2

    Rx CxLx

    CoCo1 Co2

    15.4MHz Q=2,432 @10MHz L{ fm =1kHz}=-112dBc L{ fm =10kHz}=-136dBc

    9.

    [

    16]

    M3M4

    M1 M2

    MRf

    Vbias2

    Vbias1

    M11 M12 M13 M14

    Vcm

    M17M18

    M16M15Output

    Input

    M5

    Wine-Glass Disk Array-Composite

    Resonator

    Wine-Glass Disk Array-Composite

    Resonatorio

    vi

    VP

    VSS = -1.65 V

    M3M4

    M1 M2

    MRf

    Vbias2

    Vbias1

    M11 M12 M13 M14

    Vcm

    M17M18

    M16M15Output

    Input

    M5

    Wine-Glass Disk Array-Composite

    Resonator

    Wine-Glass Disk Array-Composite

    Resonatorio

    vi

    VP

    VSS = -1.65 V

    62MHz Q=118,900 @13MHz L{ fm =1kHz}=-140dBc L{ fm =10kHz}=-150dBc

    [22] 128

    (Medium-Scale Integrated Micromechanical Circuits)

    4CMOS-MEMS [23]

    (Timing Reference)

    Q (Frequency Stability)(Phase Noise)

    Q 3 [14][16]

    [16] Q 118,900 TSMC 0.35-m

    (Transresistance-Sustaining Amplifier)

    GSM

  • 17

    CMOS-MEMS

    Foundry- MEMS CMOS-MEMSCMOS-MEMS Dr. Gary K. Fedder ( Carnegie Mellon University ECE )Fedder Foundry CMOS

    Release CMOS MEMS CMOS 4 [23]

    Universitat Autnoma de Barcelona (UAB) 1GHz [24] CMOS Foundry CMOS-MEMS

    MEMS

    Q () CMOS Foundry RF MEMS

    Prof. Clark T.-C. Nguyen ()

    [1] P. Orsatti, et al., A 20-mA-receive , IEEE J.

    Solid-State Circuits, vol. 34, no. 12, pp. 1869-1880,

    Dec. 1999.

    [2] A. A. Abidi, Direct-Conversion , IEEE J.

    Solid-State Circuits, vol. 30, pp. 1399-1410,

    December 1995.

    [3] C. P. Yue, et al., On-Chip Spiral , IEEE J.

    Solid-State Circuits, vol. 33, no. 5, May 1998, pp.

    743-752.

    [4] J. C. Rudell, et al., A 1.9-GHz , IEEE J.

    Solid-State Circuits, vol. 32, no. 12, pp. 2071-2088,

    Dec. 1997.

    [5] C. T.-C. Nguyen, Vibrating RF , Proceedings,

    2004 IEEE Custom Integrated Circuits Conf.,

    Orlando, Florida, Oct. 3-6, 2004, pp. 257-264.

    [6] W. C. Tang, et al., Laterally driven , Sensors

    and Actuators, 20, 25-32, 1989.

    [7] F. D. Bannon, et al., High-Q HF , IEEE J. Solid-State

    Circuits, vol. 35, no. 4, pp. 512-526, April 2000.

  • 18

    [8] K. Wang, et al., VHF free-free , IEEE/ASME J.

    Microelectromech. Syst., vol. 9, no. 3, pp. 347-360,

    Sept. 2000.

    [9] Y.-W. Lin, et al., Series-resonant , IEEE J.

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