RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
NanoWal day (UCL, Louvain-la-Neuve) 18.03.2008 1
Harrie [email protected]
--
NanoWal-Microsystems Chair event
UCL, Louvain-la-Neuve, 18 March 2008
RF-MEMS: An enabling
technology for reconfigurable
radio front-ends
H. Tilmans imec/restricted 2008 2
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Overview
• Mobile phones à handsets– Intro/Ubiquituous world/Convergence
– Multiband/Multistandard/Multimedia
– Challenges for the future/Key drivers for mobile handsets
• Technology trends addressing the handset problem
• RF-MEMS as an enabling technology– How can RF-MEMS help?
– Example of MEMS devices for wireless applications
– Example of reconfigurable MEMS based functionality (switchable bandpass filter)
– Passive integration of RF-MEMS
• Conclusions
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
NanoWal day (UCL, Louvain-la-Neuve) 18.03.2008 2
H. Tilmans imec/restricted 2008 3
NanoWal-Microsystems-day UCL, Louvain-la-Neuve (Belgium) 18.03.2008
Cellular radios:
Not just phones anymore!
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Wireless Ubiquity: a world where we can access what we
want, when we want and where we want..
Source: K. Muhammadand, Front-Ends for Commercial Digitally Controlled Radios”, workshop IMS2007
Multi-MEDIA
Multi-BAND
Multi-STANDARD
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
NanoWal day (UCL, Louvain-la-Neuve) 18.03.2008 3
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A crowded frequency spectrum
Source: M. Brandolini (Broadcom) and F. Svelto, “Reconfigurable Reconfigurable SiSiRF Receiver FrontRFReceiver Front--Ends Ends for Multifor Multi--Standard RadiosStandard Radios”, Workshop IMS2007.
• Cellular (GSM-GPRS, UMTS/WCDMA, …)• Connectivity (Bluetooth, Wi-Fi, WLAN, WiMAX)
• Broadcast (FM, DVB,..)• Positioning (GPS)
UWBbroadcast
H. Tilmans imec/restricted 2008 6
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Roadmap for RF section in cellular “phones”
Source: EPCOS, “RF-Frontendof Mobile Phones”, workshop IMS06
High level of integration is a must!
Baseband
Baseband
Ba
tte
ry l
ife
2011
Baseband
Baseband
RF
BB
TunabilityReconfigurableFront-end, SDR
SoC,Adv. Packaging Modular, SiP
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
NanoWal day (UCL, Louvain-la-Neuve) 18.03.2008 4
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Trends/Emerging disruptive technologies with
the potential to simplify the RF front-end:
• IC trend:– Miniaturization “More Moore”: 90à 65à 45à 32nm (à SoC approach)
– New technologies “Beyond CMOS” (e.g., tri-gate, Carbon Nanotube FET)
• Packaging trend (SiP is the future):– Advanced packaging technologies:
• Smaller pich (wirebond and flip-chip)
• Thickness direction integration– Stacked die (PiP, PoP, ..), 3D packaging
– Embedded actives (thinned die) in substrate
– Embedded passives in substrate à Integrated Passive Devices (use of semiconductor processing in stead of surface mount devices)
• RF-MEMS technology: a “More than Moore” technology for building RF passives (switches, varicaps, resonators, filters, …) using semiconductor like technologies
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So many discrete passives….
àààà Integrated Passive Device (IPD)
Discrete Passives(C’s, L’s, R’s, filters, ..):
• ∼80% of all components (∼ 5% are actives)
• ∼ 70% board space• ∼ 60% cost
Spiral Inductor L
BCB
CuNi/AuCu
Al
Source: Imec
High Res subTa2O5 capacitor CTaN resistor R
Trend:Reduction of the number of discrete passives
passive integration IPD
P F-E Module
IPD inc.
P F-E ModuleIPD inc.
Passive Front-End ModuleIPD inc.
Passive Front-End ModuleIPD inc.
Spiral Cu inductor
L = 0.6 - 80 nH; Q = 30 - 150
CPW Lange coupler
Ta2O5 capacitor
5.5 pF/ mm2
0.72 nF/mm2
Gain30%boardspace
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
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Example of Integration of passives:
Philips GSM PA module àààà Tx Front-End Module
Single-band GSM PA module Quad-band Tx module
Philips, BGY241 Philips, BGY5041998 2004
IPDsPASSI
Trend towards fully integrated RF radio
module
Philips
- 2 actives- 30 SMDpassives
GSM PA+ matching+ ASW (pin diode switches)+ diplexer+ LPFs
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Multiradio: How to fit all these radio’s in the same size (or smaller) handset?
Radio 1Radio 2
Radio 3 Radio 4NOKIA
Future: 2G/3G/3.9G (up to 17 bands) together withUWB, WLAN, RFID, Bluetooth, FM Radio, DVB-H, GPS, …
Baseband
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
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Multi-band/Multi-mode radio architecture:
Today: Duplication of part of the front-end
GSM1800 Rx
UMTS2.2
GSM900 Rx
800-900MHz
1700-2200MHz
5200MHz
VHF
2400MHz
Mobile TV& Radio Rx
Multi-band antenna + Antenna switch matrix
Headphone+FM antenna
WLAN5.2 Rx
GPS Rx
LNA1
T
R
LNA4
T/R
Mode/Band switch
T
R
LNA5
PCS1900
PA1
PA2
PA3
PA5
PA4
LNA2
LNA3
GSM1800 Tx
GSM900 Tx
WLAN5.2 Tx
Direct convers
ion
BASEBAND
FDD
TDD
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The Future: The flexible radio (Multi-band/Multi-mode):
Introduce reconfigurability
UMTS2.2
GSM900 Rx
800-900MHz
5200MHz
VHF
2400MHz
Mobile TV& Radio Rx
Multi-band antenna + Antenna switch matrix
Headphone+FM antenna
GPS Rx
T
R
LNA2
T/R
Band/TDD/FDD
T
R
LNA3
PCS1900
PA1
PA3
PA2
LNA1
DCS1800 Tx
GSM900 Tx
WLAN5.2 Tx
DCS1800 Rx
WLAN5.2 Rx
Direct convers
ion B
ASEBAND
FDD
TDD
PA match
1700-2200MHz
Adaptive Antenna Match
detector
control
Tunable network
Coupler
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
NanoWal day (UCL, Louvain-la-Neuve) 18.03.2008 7
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RF-MEMS: An enabling technology for
reconfigurable radio front-ends
• Large variety of functions (switch, varicap, variometer, filter, resonator, …)à replace existing components with cheaper or better MEMS components
• Low loss (high-Q) components
• High linearity
• Reconfigurability is a natural asset for someØ Tunable/adaptive (matching) networks
Ø Multi-mode/Multi-band switching
• “Integratability”:– With IPD
– Above/Below RF-CMOS
Tunable RF blocks based on RF-MEMS
RF-MEMS switch
Tunable/Reconfigurable radio front-ends are needed to satisfy the constraints on size, battery life, functionality and cost;
RF-MEMS is a key technology enabler:
H. Tilmans imec/restricted 2008 14
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Multi-band/Multi-mode radio architecture:
Where can RF-MEMS be used?
GSM1800 Rx
UMTS2.2
GSM900 Rx
800-900MHz
1700-2200MHz
5200MHz
VHF
2400MHz
Mobile TV& Radio Rx
Multi-band antenna + Antenna switch matrix
Headphone+FM antenna
WLAN5.2 Rx
GPS Rx
LNA1
T
R
LNA4
T/R
Mode/Band switch
T
R
LNA5
PCS1900
PA1
PA2
PA3
PA5
PA4
LNA2
LNA3
GSM1800 Tx
GSM900 Tx
WLAN5.2 Txswitchplexer
RF filters
Diplexers
Direct convers
ion
BASEBAND
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
NanoWal day (UCL, Louvain-la-Neuve) 18.03.2008 8
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NanoWal-Microsystems-day UCL, Louvain-la-Neuve (Belgium) 18.03.2008
Reconfigurable Radio Front-End
Where can RF-MEMS be used?
UMTS2.2
GSM900 Rx
800-900MHz
1700-2200MHz
5200MHz
VHF
2400MHz
Mobile TV& Radio Rx
Multi-band antenna + Antenna switch matrix
Headphone+FM antenna
GPS Rx
T
R
LNA2
T/R
Band/TDD/FDD
T
R
LNA3
PCS1900
PA1
PA3
PA2
LNA1
GSM1800 Tx
GSM900 Tx
GSM1800 Rx
WLAN5.2 Rx
switchplexer
Diplexers
Tunable Matching networks
Direct convers
ion
BASEBAND
Tunable/switchable RF filters/switched filter bank
WLAN5.2 Tx
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RF-MEMSfor
Reconfigurable Radio Front-ends
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
NanoWal day (UCL, Louvain-la-Neuve) 18.03.2008 9
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RF-MEMS functionalities
• Components:– Switch
– Tunable capacitor
– Tunable inductor
– MEM resonator
– BAW resonator (FBAR)
• Circuits:– FBAR filter
– Switchable filter
– Tunable matching network
• Subsystems– Tunable antenna
– Switched filter bank
– …..
OhmicMEMS relays
FBARfilters
Switched Filter Bank
FBAR filter (Infineon)
MEM resonator
NXP
RF
5/02
RadantMEMS
IMEC
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BAW thin film resonators/filters
FBAR filter (Infineon)
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
NanoWal day (UCL, Louvain-la-Neuve) 18.03.2008 10
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The radio front-end;
where can BAW filters be used? àààà diplexer
UMTS2.2
GSM900 Rx
800-900MHz
5200MHz
VHF
2400MHz
Mobile TV& Radio Rx
Multi-band antenna + Antenna switch matrix
Headphone+FM antenna
GPS Rx
T
R
LNA2
T/R
Band/TDD/FDD
T
R
LNA3
PCS1900
PA1
PA3
PA2
LNA1
DCS1800 Tx
GSM900 Tx
WLAN5.2 Tx
DCS1800 Rx
WLAN5.2 Rx
Direct convers
ion B
ASEBAND
FDD
TDD
PA match
1700-2200MHz
Adaptive Antenna Match
detector
control
Tunable network
Coupler
Diplexers
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Ladder-type FBAR filter FBAR filter,
Infineon (2003)
Measured filter response
IL<3.5dBChip size: 0.6x0.9mm2
3.5 stage ladder filter (DCS/PCN1800 Rx (1805-1880MHz)
Infineon
Film Bulk Acoustic Resonator (FBAR) (1)
principle of operation/filter structure
• Resonator
• Filter
|Z|
ωωm inωmax
V
electrode
piezoelectric layer
~2
vf
d
d
AlN: v≈≈≈≈11,000 m/s
2.5µµµµm ŁŁŁŁ 2.2GHz
Q≈1000
resonance
anti-resonance
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
NanoWal day (UCL, Louvain-la-Neuve) 18.03.2008 11
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FBAR filter
Example AVAGO Quintplexer (5 FBAR filters)
(800MHz)
(1900MHz)
(1900MHz)
(1900MHz)
(1575MHz)
Features:• Single antenna connection for PCS duplexer, Cellular duplexer, and GPS filter• Eliminates antenna switching• Miniature size
o 5 x 8 mm Footprinto 1.3 mm Max Height
• High Power Ratingo +33 dBm Max Tx Power
• Lead-Free Construction
<5mm
<8mm
PCSRx
PCSTx
GPSGPS
CellRx
CellTx
Chip capacitors
ACFM-7101
2007
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Tunable FBAR
CsFBAR
Cs
Rm
Lm
Cm
C0
Re
R0
V
I
mmCL
10 =ω
6.29
6.28
6.27
6.26
6.25
6.24
series
reso
na
nt frequency
f s
(G
Hz)
2015105
actuation voltage (V)
pull-in
∆f=24.5 MHz(0.39% tuning)
fitted curve
signal line
substrate
bottom electrode
Cs air gap
AlNlayer
top electrode
signal line
W. Pan, P. Soussan, B. Nauwelaers and H.A.C. Tilmans, Sensors and Actuators A, vol. 126, 2006, pp. 436-446
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
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FBAR(2): FBAR filter above BiCMOS for use in
WCDMA zero-IF Front-end J. F. Carpentier, et al. (STMicroel., CEA-LETI, CSEM), “A SiGe:C BiCMOS WCDMA Zero-IF RF Front-End Using an Above-IC BAW Filter” ISSCC2005, pp.394-395
AlN
loading
0.25 µm SiGe BiCMOS wafer
SiO2
FBAR integrated above CMOS
Insertion loss-3.5dB
Out-of-band
rejection: ≈50dB
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Mechanical ResonatorSi-MEM resonator
VTT
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
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size: 10 mm x 10 mm x 2 mm
Quartz crystal oscillator (13 MHz)
•advantages: well understood, low cost (<0.5 EUR),
temperature stable to 1 ppm, long term stable to 0.1 ppm/year
•disadvantage: significant space consumer on circuit board!
Reference resonator (used for LO)
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Reference clock/Timing devices:
Quartz crystals àààà Si MEM resonators
Quartz crystals -- Remarkable properties:• high spectral purity (low phase noise),• exceptional frequency stability against temperature variations and aging (for wide temperature range (-45°C to +100°C) stability ∆f/f of XO: 10-50ppm, of TCXO: 1ppm (aging 0.1-1ppm/year) and of OCXO: 0.01ppm)
but also drawbacks:• Relatively large size• Not “integratable” (with CMOS)• Cost
New kid on the block: Si MEM resonator
MEMSMEMS
CMOSCMOS
Kajakaari (VTT, 2004)
Square Extensional Mode resonator
-2 kHz -1 kHz f0 +1 kHz +2 kHz-20
-15
-10
-5
0
5
10
15
20
Frequency
|S2
1|[
dB
m]
|S2
1| (d
B)
Frequency
f0 = 13.1 MHz
Q = 130 000
Size: 320 µm
Noise floor:-150dBc/Hz
Better than:-130dBc/Hz@∆∆∆∆f=1kHz
(=GSM spec)
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
NanoWal day (UCL, Louvain-la-Neuve) 18.03.2008 14
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SiTime
MEMS first resonator (below-CMOS)
• 300µm on the side
• 8” SOI wafers in a 0.18micron CMOS fabrication line (10cents/mm2)• Encapsulated on-chip à low cost plastic injection molded package• Performance similar to quartz (Q=75,000; frequency error 75ppm)
MEMS First resonator stacked on a CMOS driver IC in a QFN-type package (~3x5x0.85mm3)
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RF-MEMS switches
• Capacitive
• Ohmic
RF-in
RF-out
Armature(bridge)
dielectric
GND
GND
substrate
signal line
RF-MEMS switching devicesTunable capacitors
IMEC
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
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The radio front-end: Where can switches/switched caps be
used? àààà band switches, T/R switches, matching networks, ….
UMTS2.2
GSM900 Rx
800-900MHz
5200MHz
VHF
2400MHz
Mobile TV& Radio Rx
Multi-band antenna + Antenna switch matrix
Headphone+FM antenna
GPS Rx
T
R
LNA2
T/R
Band/TDD/FDD
T
R
LNA3
PCS1900
PA1
PA3
PA2
LNA1
DCS1800 Tx
GSM900 Tx
WLAN5.2 Tx
DCS1800 Rx
WLAN5.2 Rx
Direct convers
ion B
ASEBAND
FDD
TDD
PA match
1700-2200MHz
Adaptive Antenna Match
detector
control
Tunable network
Coupler
switchplexer
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A key element for reconfigurable radio front-
ends: (RF-MEMS) Switching device
DC+RF
GND
GND
dielectric
metal bridgeRF
5/02
ON
Variable capacitor
Capacitive switch
OFF
LsCfres
π2
1=
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
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Switching Devices:
Example 6-7GHz shunt capacitive switch
CLf
s
resπ2
1=
Cu 2µm/
Ni 3 µm /
Au 300nm
Probe pad
probe
TaN (0.2µm)
Metal armature (Al-alloy 1µµµµm))
Ta2O5 (0.3µm)
Al (0.3µm)AF45 (700 µµµµm)
Interconnect (Al-1µm)
Air gap
Cu/Au frame
Substrate
RF-in
RF-out
RF-out
RF-in
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Imec’s RF-MEMS Technology Platform today:
First step towards an RF-MEMS IPD
Ta2O5 capacitor
0.72 nF/mm2
Spiral Al inductor
L=0.6-80nH
Q=5-40
TaN resistors
25-100 ΩΩΩΩ/oooo
0.7-37 kΩΩΩΩ
Cu 2µm/
Ni 3 µm /
Au 300nm
Probe pad
probe
TaN (0.2µm)
Metal armature (Al-alloy 1µµµµm))
Ta2O5 (0.3µm)
Al (0.3µm)AF45 (700 µµµµm)
Interconnect (Al-1µm)
Air gap
Wafer-level packaging
Tunable capacitor
Boosted Capacitive switches/switched capacitors (0.5-50GHz)
shunt
series
Capacitive switches/ switched capacitors (5-50GHz)
Longitudinal shunt
Transversal shunt
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
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RF-MEMS circuitry
Switchable (LC-type)Band Pass Filter
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The radio front-end: Where can switchable filters
be used? àààà band select filters
UMTS2.2
GSM900 Rx
800-900MHz
5200MHz
VHF
2400MHz
Mobile TV& Radio Rx
Multi-band antenna + Antenna switch matrix
Headphone+FM antenna
GPS Rx
T
R
LNA2
T/R
Band/TDD/FDD
T
R
LNA3
PCS1900
PA1
PA3
PA2
LNA1
DCS1800 Tx
GSM900 Tx
WLAN5.2 Tx
DCS1800 Rx
WLAN5.2 Rx
Direct convers
ion B
ASEBAND
FDD
TDD
PA match
1700-2200MHz
Adaptive Antenna Match
detector
control
Tunable network
Coupler
Tunable/switchable RF filters/switched filter bank
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
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Example of an IPD:LC-type BPF (GPS and Galileo)
0.6mm
Galileo
GPS5.34nH 5.34nH
6.45pF
2.58pF
53.7pF
38.9pF
2pF 5.6pF
Ci
n
Ci
n
C
S
C
S
C
C
LR LRCR CR
CCCCININININ CCCCSSSS LLLLRRRR
GNDGNDGNDGND----GNDGNDGNDGNDBridgeBridgeBridgeBridge
PadPadPadPad
CCCCRRRR CCCCCCCC CCCCRRRR LLLLRRRR CCCCININININCCCCSSSS
GNDGNDGNDGND----GNDGNDGNDGNDBridgeBridgeBridgeBridge PadPadPadPad
Source: X. Rottenberg et al., proc. EuMC2006, Manchester (UK), Sept. 2006
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2nd order LC-type BPFs as IPD:for GPS and Galileo
90.5 (94.3)
1587 (1576)
7.3 (5.1)GPS (1575MHz)
109 (105)1130 (1203)
6.0 (4.3)Galileo (1202MHz)
BW (MHz)CF (MHz)IL (dB)
GPS
Galileo
MCM-D IPD:
Ø Two separate filters for both bands
àààà increased size
Need for on-chip switchable capacitor(for CR and CC)
RF-MEMS
(…) simulation
GPS
Galileo
S2
1[d
B]
Freq. [GHz]
3-switch CinCin
CS CSCC
LR LRCR CR
Source: X. Rottenberg et al., proc. EuMC2006, Manchester (UK), Sept. 2006
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
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Switchable filter in RF-MEMS:between GPS and Galileo bands
CinCin
CS CSCC
LR LRCR CR
Source: X. Rottenberg et al., proc. EuMC2006, Manchester (UK), Sept. 2006
GPS
Galileo
3-switch
5.97.3GPS (1575MHz)
4.86.0Galileo (1202MHz)
IL [dB]
RF-MEMS
IL [dB]
MCM-D
Comparison IPD/RF-MEMS
• (+) Reduced size (by factor 2)
• (+) Lower loss
• (-) fo (Galileo) is off
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Lr
Cr-Cm
n:1CmZo
Cr-Cm
1:n
Zo
Lr
Vg
PARAMETER DCS 1800
Lr (nH)
Cr (pF)
Cm (pF)
2.6
n
2.6
2.85 0.28
0.2 0.045
5 1.85
WLAN
CNRS-IRCOM (co-simulation at TUM)[email protected] at MEMSWAVE2006
Tunable/Switchable BPF
2-COUPLED RESONATOR switchable FILTER by XLIM (1)
B. Switchable filter,using coupled
lumped resonators
Switched capacitorsImpedance transformer
1 2 3 4 5 6 7 8 90 10
-40
-20
-60
0
Frequency (GHz)
S p
ara
mete
rs(d
B) Std. 2:
WLAN5.2GHz
Std. 1:DCS1800
ADS simulation
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
NanoWal day (UCL, Louvain-la-Neuve) 18.03.2008 20
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CNRS-IRCOM (co-simulation at TUM)[email protected] at MEMSWAVE2006
Tunable/Switchable BPF
2-COUPLED RESONATOR switchable FILTER by IRCOM (2)
2 cm
MEMS switchable capacitor
MEMS DC contact switch
Switchable inter resonator
coupling capacitanceSwitchable Filter core layout
SMD inductor
1360 m
760 m
Surface Mounted high Q
inductor
Input matching section
Output matching section
Filter core
SM inductorsQ=156 @ 1.7GHz
Prototype fabricated by XLIM (on quartz substrate: 525 m, ε r=3.78,
tanδ =0.0001) and measured
Fixed value MAMcapacitor
L=2.6 nH
Measured characteristics
1 2 3 4 5 6 7 80 9
-60
-50
-40
-30
-20
-10
-70
0
-25
-20
-15
-10
-5
0
5
-30
10
Frequency (GHz)
S2
1 (
dB
) S1
1 (d
B)
Surface Mounted high Q
inductorInput matching
section
Output matching section
Filter core
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RF-MEMS on the evolutionary path of passive integration
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
NanoWal day (UCL, Louvain-la-Neuve) 18.03.2008 21
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Technology platform for RF passives:
Stepwise introduction of flexibility/Evolutionary paths
Ø Integration of fixed RF passives à Integrated Passive Device MCM
Spiral Cu inductor
L = 0.6 - 80 nH; Q = 30 - 150
CPW Lange coupler
Ta2O5 capacitor
5.5 pF/ mm2
0.72 nF/mm2
Spiral Inductor L
BCB
Cu
Ni/Au
Cu
Al
Source: Imec
High Res substrate
Ta2O5 capacitor CTaN resistor R
MCM
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Technology platform for RF passives:
Introduction of flexibility/Evolutionary paths
Ø Integration of fixed RF passives à Integrated Passive Device MCM
Ø Preferably serve as a carrier substrate for mounting actives (and other discrete passives) à RF-SiP (or RF MCM-D)
Spiral Inductor
BCB
Mounted component, e.g. RFIC
Cu
Ni/Au
Cusolder
Al
Source: Imec
High Res substrate
Ta2O5 capacitorTaN resistor
e.g. SAW
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
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Example of RF-SiP reconfigurable
front-end
Tunable BPF (XLIM)
LNA (ULM/ATMEL)
Tunable Matching Network (METU)
Antenna (IMEC, KU Leuven)
Diplexer(Avago)DPST (FBK)
SPDT (METU)SPDT (METU)
Rogers 4350
Prepreg 7628
FR4
Prepreg 7628
Cu layer
RF-ground
DC lines
Microstrip lines #1
#2
#3
#4
Rogers 4350
Prepreg 7628
FR4
Prepreg 7628
Cu layer
RF-ground
DC lines
Microstrip lines #1
#2
#3
#4
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NanoWal-Microsystems-day UCL, Louvain-la-Neuve (Belgium) 18.03.2008
Technology platform for RF passives:
Introduction of flexibility/Evolutionary paths
Ø Integration of fixed RF passives à Integrated Passive Device MCM
Ø Preferably serve as a carrier substrate for mounting actives (and other discrete passives) à RF-SiP
Ø Next evolutionary path: include RF-MEMS (flexible) passives:
§ Hybrid à RF-MEMS SiP
Spiral Inductor
BCB
Mounted component
Cu
Ni/Au
Cusolder
Al
RF-MEMS
Source: Imec
High Res substrate
Ta2O5 capacitorTaN resistor
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
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Spiral Inductor
Mounted component
Cu
Ni/Au
Cusolder
Al
CAP
BCB
High Res substrate
Ta2O5 capacitorTaN resistor
Technology platform for RF passives:
Introduction of flexibility/Evolutionary paths
Ø Integration of fixed RF passives à Integrated Passive Device MCM
Ø Preferably serve as a carrier substrate for mounting actives (and other discrete passives) à RF-SiP
Ø Next evolutionary path: include RF-MEMS (flexible) passives:§ Hybrid à RF-MEMS SiP
§ Monolithic à RF-MEMS MCM/RF-MEMS SiP
switch
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NanoWal-Microsystems-day UCL, Louvain-la-Neuve (Belgium) 18.03.2008
Conclusions and outlook
• Mobile wireless communication systems (handsets) are complex embedded systems where all functional blocks are custom-made for mobility. The combination of miniaturization and functionality is unprecedented compared to other consumer products.
• Next-generation mobile handsets will accommodate multiple wireless standards (3G, WiFi, WiMax, DTV, ..) and multiple frequency bands and will be based on software-defined-radio (SDR), asking for
– A reconfigurable RF interface/architecture
– Mode/band switching, Tx/Rx switching
– More and smaller antennas àààà antenna impedance matching
– More and higher efficient PAs àààà PA impedance matching
– Tunable/switchable filters
– ……
• There is a need for reconfigurable/tunable RF components (L’s, C’s, filter, switch, …);
• RF-MEMS is a key enabling (disruptive) technology for reconfigurable radio front-ends satisfying functionality requirements, miniaturization, reduction of component count, long battery life, improved electrical performance, low cost, ….
• High integration level / “Integratability” (with CMOS and/or as passive platform) is one attractive feature of RF-MEMS technology
• The state of RF-MEMS in handsets:
– BAW fixed frequency filters based on FBAR/SMR have proven themselves; Fixed frequency filters based on mechanical resonators are still very far from industrialization
– Silicon (BAW) resonators are emerging to replace quartz crystal resonators, but very tough stability requirements
– RF-MEMS switch technologies still requires proof for RF applications. There still remains research work to be done in terms of: Packaging, reliability (stiction, switch life cycles), power handling, price (low cost wafer process (foundry compatible) and packaging process needed)
– Implementation of switchable filter banks are hampered by the development stage of MEMS switches
– Tunable RF filters are still very far from implementation;
– …….
RF-MEMS: An enabling technology for Reconfigurable Radio Front-ends
H. Tilmans (IMEC)
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MEMS design: Gerard Klaasse (now Sensata), Wanling Pan (now GTU), Laurent Francis (now
UCL), Kris Verheyen, Steve Stoffels
RF design: Xavier Rottenberg, Geert Carchon, Kristof Vaesen, Steven Brebels, Walter De Raedt
Technology: Philippe Soussan, Philip Ekkels, Laurent Francis (now UCL), Gerard Klaasse (nos
Sensata), Kris Verheyen, Philip Nolmans, Henri Jansen (now UT), Ann Witvrouw
Packaging: Anne Jourdain, Piet De Moor, Serguei Stoukatch, Eric Beyne
Materials and Reliability: Piotr Czarnecki, Stanislaw Kalicinski, Robert Modlinski, Ann
Witvrouw, Ingrid De Wolf
System design: Kristof Vaesen, Piet Wambacq
Acknowledgements - the IMEC RF-MEMS team
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Thank YouThank YouThank YouThank You