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Satellite telecommunication links cover astounding distances; ESA missions need to communicate with spacecraft orbiting at distances up to 900 million kilometres away. The uplink signal must be strong enough to travel these enormous distances and still deliver data to a satellite's receiver. High Power Amplifiers (HPAs) are used at ESA ground stations to provide the requisite high power levels required for the uplink. HPAs have certain distinctive characteristics. They are heavy (up to 1500 kg), energy intensive (up to 100 kW) and they must be handled with a lot of care - any mishandling can lead to severe damage not only to the amplifier itself but also to the station - or, in the worst case, even cause serious injuries or death station personnel. This forum provides a short introduction to high-power amplifiers and their technology, to solid state power amplifiers, why we still use klystrons (a vacuum tube invented in the 1930s) and the usage of HPAs at ESA ground stations.
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S.Marti, OPS-GSS 25/09/2009,
Power amplifiers:
The last kingdom of Vacuum Tubes
Present and future of Power Amplifiers in ESTRACK
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S.Marti, OPS-GSS 25/09/2009,
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About ….
– This is a forum about Hardware, not only hard, but also heavy, bulky and (when working) very hot!
– We will talk about Transistors and also … vacuum tubes (in the XXIst century!)
– No acronyms (OK, only three: HPA, SSPA and KPA)
– No formulas – A lot of pictures, so …
Enjoy the show!
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S.Marti, OPS-GSS 25/09/2009,
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What is a powe r amplifie r
❖ Provides to the RF signal the required power level to reach the satellite with enough strength
❖ Transform electrical power (from mains supply) into RF power❖ Capital performance: Efficiency
❖ High power handled -> High power consumed and dissipated❖ The consumed power not transformed in RF power shall be
dissipated❖ Limitations may come from maximum electrical field (peak
power) or maximum thermal dissipation (average power)
consumedpowerMains
deliveredpowerRF=η
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S.Marti, OPS-GSS 25/09/2009,
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What happe ns if we don’t take care
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Why we ne e d a powe r amplifie r
❖ High power required to compensate path losses over 100’s million kilometres (Mars is between 50 and 400 million km) -> 270 dB of signal attenuation in the path.
❖ How much power is received?– Transmission of 20 kW– X Band (7.190 MHz)– Power focused in a narrow beam (64 dB gain of a 35m antenna)– Satellite antenna of 0.8 meters (33 dB antenna Gain)
Total power collected by the antenna: -100 dBm!! That is 0.1 pWatts
And … this is not the worst case!
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Whe re is the powe r amplifie r
❖ New Norcia
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Type s of Powe r amplifie rs
❖ HPA: High Power Amplifier❖ SSPA: Solid State Power Amplifier❖ KPA: Klystron Power Amplifier❖ Magnetrons, Travelling wave tube❖ Gyrotrons, …(2 to > 200GHz)
❖ Other uses of Microwave high power amplifiers
– Radar– Nuclear magnetic resonance (NMR) – Microwave ovens– Induction furnaces– Nuclear fusion research (plasma heating)– Particle accelerators– Plasma discharge devices– Weapons (Active Denial System, ADS)
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S.Marti, OPS-GSS 25/09/2009,
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Ele me nts of a S S PA-0.5
57
Sortie RF / Output RFWR430
Info PR / R/P InfoInfo PS / O/P Info
Test PS
Outputpower sample
Sortie analogiqueAnalog output
Détection ROSVSWR detection
Combi-
neur4
voies
4 way combi-ner
DNS2030
Divi-seur
4 voies
4 way divider
RF switch
Entrée RFRF input
TélégestionRC&M
Télégestion
RC&MSupervision
Supervision
Cartes gestion / Control boards
-4 -2 -2+44 +28.5
-1-2
-1 -5 -10 34 32 4x24 4x52.5
dB
dBm
DNS2030
DNS2180
G 1 dB
P 1 dB
Minimum
Réseau / Mains240 V50 / 60 Hz
Commu-
tateurRF
Diviseur 2 voies /
Two ways divider
DNS2180
DNS2180
DNS2180
Atténuateurvariable0-30dB
Variable attenuator
LimiteurLimiter
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Ele me nts of a KPA
inrushcurrentlimiter
preamplification and monitoring part TPGDNK7703
keyboard+
screen
control boards
usersupervision
RC&M
mains
limiter
Pe
variableattenuator
preamplifier 1 preamplifier 23dB90°
RFswitch
RF power part TDNK7703
RF input
TCP/IP
7U, 30kg
Klystron
arc detector
circulator
harmonicfilter
detection50dB
coupler
50dBcoupler
N RF sample
Ps
50dBcoupler
control boards
detection
PsPr
serialbus
heater supply
blower
arc detectionboard
power supply part DAL8000/K
high voltagesfiltering board
mains AC/DC15V
mains cut offboard
control, alarm andregulation board
filtering
measures
pwm
K
C2
C3
5U, 55kg
resonantinverter
currentmeasure
board
mains
circuitbreaker+mains
filter
rated level
-10dBm
-16.5dBm
-20dBm
28dBm
26.5dBm
65dBm
64.2dBm
measures
DFTS
T measure
11U, 65kg
RS422
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What a S S PA looks like
❖ Old, Si BJT; ❖ Now AsGa, LDMOS-Si❖ Coming GaN and SiC
❖ Architecture: – Driver chain– Parallel power
stages– combiner (Radial,
corporate, spatial combiner)
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S S PA te chnolog ie s
❖ Different materials (Si, AsGa, GaN, SiC, …)❖ Different transistors (LDMOS, MESFET, HEMT, …)
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How works a Kly s tron?
❖ Thermoionic device (works around an electron beam)❖ Very high voltages and strong magnetic fields involved
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What a Klys tron Looks Like ?
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Are the klys trons so old?
Russell and Sigurd Varian invented the klystron in August 1937 at Stanford University, based on the velocity modulation theory from A.Arsenjewa-Heil and Oskar Heil (wife and husband) (1935) and Hansen works on electrons focusing and acceleration
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Klys tron limits (TH2089)
❖ Use in synchrotron applications❖ 1.3 MW CW at 350 MHz❖ 100 kV Beam voltage, 20 A❖ 5 meters long, 2500 kg
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Klys tron limits (TH2100-TH2155)
❖ Use in synchrotron
applications❖ 45 Mw peak, 20 kW average at
3 GHz❖ 300 kV Beam voltage, 340 A❖ 70 kg, 1.65 meters❖ 80 kg, 1.5 meters
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Klys tron limits (VKX7864A)
❖ Interplanetary Radar Applications
❖ IEEE MTT Vol 48no 6 June 1992❖ VKX 7864A❖ 250 kW @ 8510 MHz❖ Collector dissipation 4.3 kW/in2
❖ 735 lb❖ 51 kV beam Voltage, 11 A❖ Efficiency 45%❖ Linearity is important
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S S PA v s . KPA
Focus magnet
Protections
Heater supply
Divider + CombinerAncillary elements
High (8kV … 200 kV)Low (10 … 50 V)Supply voltage
Single Point FailureGraceful degradationdegradation
~ 20.000 hours
(Tube exhaustion)
> 100.000 hoursReliability
> 1 MW (L Band)~300 W/TRT (L Band)
~ 2 KW amplifier
Max. Power (L Band)
~ 100 GHz~ 20 GHzMax. Frequency
1937~ 1980’sOrigins
KPASSPA
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ESTRACK Amplifie rs
❖ S Band (2025-2120 MHz)– S-SSPA 500 W– S-LPA 2 kW – S-HPA 20 KW
❖ Ka Band (34200-34700 MHz (future)
– Ka-KPA 500 W
❖ X Band (7145-7235 MHz)– X-SSPA 500 W– X-LPA 2 kW – X-HPA 20 KW
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COTS for ESA?
ESA employs the following bands:❖ S Band (2025-2010 MHz):
– Also used by commercial operators. Increasing restrictions– COTS available up to 500 … 2kW– 20 kW only used by Agencies in Deep Space (no COTS)
❖ X Band (7145-7235 MHz)– Band only for Agencies’ use (no commercial operators)– No commercial COTS in the market– 20 kW only used by Agencies in Deep Space (no COTS)– Closer cots are military bands (7.9 to 8.4 GHz)
❖ Ka Band (34200-34700 MHz)– Same problematic than X Band (only Agencies)– Closer cots are Ka Uplink bands (27 – 31 GHz ) – Less developed than X Band
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S -S S PA 500 W
❖ DNS 2400– Old unit from the 80’s– Still working in KRU, KIR, PER, VIL– Modular– Graceful degradation– redundant preamplifier
❖ DNS 2703– Installed in MSP and RED– Will be installed in NNO– Smaller– Cheaper– TCP-IP– Additional functions (O/P power TM,
Log File, ALC, …)– More reliable (we expect, still not time
to verify!!)
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S -LPA 2 kW
❖ Old DNK 2703– NNO, KRU and VIL-2– Obsolete. No maintainable– K3S64D (Only possible
COTS)
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S -HPA 20 KW
❖ Needs a DI cooling system
❖ 203-S from ETM in NNO
❖ Single unit in the network
❖ No way to transmit S band 20 kW in other station (regulatory issues)
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X-S S PA 500 W
❖ DNS 7703/500 from SODIELEC– Developed end of 90’s– Modular– double preamplifier– Graceful degradation
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X-LPA 2 kW
❖ DNK 7703 for NNO and DS3❖ K3C for CPI (COTS) for CEB❖ Former RSI and Vertex units already
removed
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X-HPA 20 kW
❖ Needs a DI cooling system❖ ETM 203-X for NNO and CEB❖ RhI TRA 000AA for CEB and DS3
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De -Ioniz e d Cooling S ys te m
❖ The cooling system is required to extract 90 kW of heat from a klystron smaller than a bottle of wine.
❖ De-ionized and very pure water required to avoid corrosion of the copper body of the tube
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Ka-KPA 500 W (future )
❖ Option for Cebreros and DS3 stations
❖ Ka Band uplink required for RS experiments of Bepi Colombo
❖ Presently still in project.
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De e p S pace S tations in the future
❖ JPL and ESA studies point to arrays as future solution to get better performances than present Deep Space Antennas
❖ Arrays demand many small to medium power amplifiers → SSPA are the natural solution
❖ Expected EIRP values in excess 1 TW (120 dBW)❖ Arraying in transmission is not completely solved ❖ Reliability, cost, repeatability, … Some parameters, previously
secondary, now become critical
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Thanks to …
❖ Andreas Scior
❖ Giancarlo Alessi
And of course …
Thank You for your attention
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… and S SA – One s te p beyond
❖ Frequency 1250 MHz (TBC)❖ Power around or over 1 MW (1 million Watts)❖ Phased array architecture: around xx modules of yy Watts each ❖ Packed in an overall dimension of cccc meters per ddd meter
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Klys tron limits (TV2022)
❖ Industrial accelerators applications
❖ 30 Mw peak, 60 kW average at 1.3 GHz
❖ 240 kV Beam voltage, 200 A
❖ 1600 kg, 1.8 meters
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Whe re is the powe r amplifie r
❖ Kourou (15 meters)❖ (Actualizar con banda X)
❖ Think if remove this slide and let only the 35 mters
