EA D S INNOVA TION W ORKS RF MEMS at EADS: Concept, Designs, and Applications Dr. Bernhard Schönlinner Dr. Bernhard Schönlinner, EADS Innovation Works Germany, +49 89-607-22075, bernhard.schoenlinner@eads.net 1
EADS Airbus Military Transport Aircraft Eurocopter Space Defence & Security Systems Tom Enders Francisco Fernández-Sáinz Lutz Bertling François Auque Stefan Zoller EADS Innovation Works 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 2
Content RF MEMS: Mode of operation Temperature stability Charging of dielectric layers Power handling Achieved performance at EADS RF MEMS designs and results at EADS RF MEMS applications at EADS 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 3
RF MEMS Switches 2 types of RF MEMS switches: ohmic switches capacitive switches Most popular actuation mechanism: electro-static ohmic switch capacitive switch 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 4
Mode of Operation Default state: cantilever in the up-state Apply DC-voltage between cantilever and pull-down electrode Electrostatic forces pull cantilever to down-state 2 µm 0.2 µm up-state Cantilever down-state Insulation layer Pull-down electrode 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 5
Mode of Operation Similar mode of operation as cantilevers 300 µm 0.8 µm 2 µm 0.2 µm down-state Insulation layer Membrane up-state Pull-down electrode 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 6
Photographs of Different Designs Fixed-fixed membrane designs 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 7
Photographs of Different Designs Cantilever designs 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 8
EADS Approach for RF MEMS Substrate: high-resistivity Silicon 200 nm of thermally grown Silicon oxide Metal cantilever with intrinsic stress curls up Backside metallisation Implantation zone for capacitive coupling Metallisation Silicon Silicon oxid Ion implantation (conductive) 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 9
MEMS Issues Macro-World Micro-World Gravitational force Vibration Acceleration Fatigue Temperature Electrostatic charges Humidity - stiction of surfaces Dust Thermal management Temperature 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 10
Temperature Stability Thermal expansion: stress! Membrane buckles Cannot operate anymore 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 11
Temperature Stability Design approaches: Cantilever design Thermal decoupling through anchor design 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 12
Charging of Dielectric Layer High electric fields across insulation layer Charges are driven into insulation layer Charges stay there and hold membrane in down-state Depends on the quality of the insulation layer!! 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 13
Charging of Dielectric Layer Design approaches: Omit insulation layer possible for ohmic switches capacitive switches: little down-state capacitance up-state down-state 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 14
Charging of Dielectric Layer Design approach: Use good dielectric: thermally grown Silicon oxid easy to fabricate well characterised highly reproducible Metallisation Silicon Silicon oxid Ion implantation (conductive) 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 15
Power Handling ( Hot Switching ) Main challange for ohmic switches: Micro-welding typically: max power 1 mw Main challange for capacitive switches: Self-actuation typically: max power < 500 mw Micro-welding Self-actuation or hold-down 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 16
Power Handling ( Hot Switching ) Design approach: Avoiding the pull-in effect Typically: pull-down voltage of 30 V -> hold-down voltage of 4.. 8 V 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 17
Power Handling ( Hot Switching ) Curled cantilever: Pull-down voltage: 30 V Hold-down voltage: 25 V -> high restoring force -> less prone to self-actuation 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 18
Reliability of EADS RF MEMS Switching cycles 10 9 switching cycles performed with no change in performance Temperature of operation No degradation after operation for 40h at 120 C Power handling >6W measured in hot switching mode 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 19
Movie 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 20
EADS RF MEMS Circuit Designs Switches Phase shifters Tunable filters and antennas 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 21
Switches for Ku- to Ka-band 0 Ku-band Microstrip Series Switch 0 S21 up-state in db -5-10 -15-20 -0.2-0.4-0.6-0.8 S21 down-state in db -25 8 10 12 14 16 18 Frequency (GHz) -1 @ 12GHz IL = - 0.2dB IS = - 17dB 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 22
High-isolation Ka-Band switch 0 0,0 Carbon line DC pad S 21 up-state [db] -10-20 -30-40 -0,5-1,0-1,5-2,0 S 21 down-state [db] -50-2,5 @35GHz IL = - 0.5dB IS = - 35dB -60 28 30 32 34 36 38 40 Frequency [GHz] S 21 up-state (measurement) S 21 up-state (simulation) S 21 down-state (measurement) S 21 down-state (simulation) -3,0 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 23
SP4T Ku-Band switch S11 and Isolation (db) Insertion Loss (db) Frequency (GHz) @ 12GHz IL = - 0.4dB IS = - 22dB 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 24
EADS RF MEMS Circuit Designs Switches Phase shifters Tunable filters and antennas input output Direction of antenna beam Phase front RF signal progressive phase delay 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 25
3-bit transmit phase shifter at Ka-band 180 90 45 Miniaturized 180 -Bit and novel 45 -bits @34GHz Phase deviation = < 13.25 Mean Insertion loss = < -2.2dB 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 26
EADS RF MEMS Circuit Designs Switches Phase shifters Tunable filters and antennas 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 27
RF-MEMS switchable patch antenna in Ka-band 0 Insert feed depth 370um S11 in db -10-20 up state down state Sim_Patch_up Sim_Patch_down -30 32 34 36 38 40 Frequency (GHz) Released area Anchor points Si Oxide f = 3.1GHz BW = 0.8Ghz down-state 1GHz up-state S11 > -1.7dB in operational range of the other state filter function 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 28
RF-MEMS switchable filter in Ka-band 0-5 S21 in db -10-15 -20 2-pole microstrip ladder filter 300 µm of the resonators are switchable -30 20 25 30 35 40 45 Frequency (GHz) 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 29-25 Sim_down Sim_up Meas MF3 down Meas MF3 up 80V Frequency shift: 20% (80 V) Insertion loss: -1.5 db (down) -1.7 db (up) -3 db bandwidth : 16% (down) 15% (up) Ripple in passband: 1.1 db
Applications of RF MEMS Circuits Electronically steerable antennas for communication Electronically steerable antennas for radar Multi-band communication and electronic counter measures 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 30
Electronically steerable antennas: for communication Scenario: Bi-directional broadband SatCom links from a mobile platform to a satellite and vice-versa. 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 31
Electronically steerable antennas: for radar Scenario: Enhanced onboard airborne sensor systems 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 32
Multi-band communication and ECM Scenario: Next generation multi-band satellite payloads, airborne radar and ECM systems 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 33
Summary Microsystems are a class of devices that find more and more access into our daily life RF MEMS switches are one example with a wide range of possible applications e.g. in aerospace Advantages are obvious Challenges still exist It is a question of time when they will be applied in many products 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 34
Thank you! 18.03.2008 Dr. Bernhard Schönlinner, EADS-IW-SI, 089-607-22075, bernhard.schoenlinner@eads.net 35