OPS Forum ESTRACK Transmitters 25.09.2009

• 1. Power amplifiers: The last kingdom of Vacuum Tubes Present and future of Power Amplifiers in ESTRACK

2. 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 XXI stcentury!)

• • No acronyms (OK, only three: HPA, SSPA and KPA)

• • No formulas

• • A lot of pictures, so

• • Enjoy the show!

3. What is a power amplifier

• 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)

4. What happens if we dont take care 5. Why we need a power amplifier

• High power required to compensate path losses over 100s 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!

6. Where is the power amplifier

• New Norcia

7. Types of Power amplifiers

• 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)

8. Elements of a SSPA -0.5 57 Sortie RF /Output RF WR430 Info PR /R/P Info Info PS /O/P Info Test PS Output power sample Sortie analogique Analog output Dtection ROS VSWR detection Combi- neur 4 voies 4 way combi-ner DNS2030 Divi- seur 4 voies 4 way divider RF switch Entre RF RF input Tlgestion RC&M Tlgestion RC&M Supervision 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 Rseau /Mains 240 V 50 / 60 Hz Commu- tateur RF Diviseur 2 voies / Two ways divider DNS2180 DNS2180 DNS2180 Attnuateur variable 0-30dB Variable attenuator Limiteur Limiter 9. Elements of a KPA 10. What a SSPA looks like

• Old, Si BJT;

• Now AsGa, LDMOS-Si

• Coming GaN and SiC

• Architecture:

• • Driver chain

• • Parallel power stages

• • combiner (Radial, corporate, spatial combiner)

11. SSPA technologies

• Different materials (Si, AsGa, GaN, SiC, )

• Different transistors (LDMOS, MESFET, HEMT, )

12. How works a Klystron?

• Thermoionic device (works around an electron beam)

• Very high voltages and strong magnetic fields involved

13. What a Klystron Looks Like? 14. Are the klystrons 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 workson electrons focusing and acceleration

15. Klystron limits (TH2089)

• Use in synchrotron applications

• 1.3 MW CW at 350 MHz

• 100 kV Beam voltage, 20 A

• 5 meters long, 2500 kg

16. Klystron 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

17. Klystron limits (VKX7864A)

• Interplanetary Radar Applications

• IEEE MTT Vol 48no 6 June 1992

• VKX 7864A

• 250 kW @ 8510 MHz

• Collector dissipation 4.3 kW/in 2

• 735 lb

• 51 kV beam Voltage, 11 A

• Efficiency 45%

• Linearity is important

18. SSPA vs. KPA Focus magnet Protections Heater supply Divider + Combiner Ancillary elements High (8kV 200 kV) Low (10 50 V) Supply voltage Single Point Failure Graceful degradation degradation ~ 20.000 hours (Tube exhaustion) > 100.000 hours Reliability > 1 MW (L Band) ~300 W/TRT (L Band) ~ 2 KW amplifier Max. Power (L Band) ~ 100 GHz ~ 20 GHz Max. Frequency 1937 ~ 1980s Origins KPA SSPA 19. ESTRACK Amplifiers

• 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

20. 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

21. S-SSPA 500 W

• DNS 2400

• • Old unit from the 80s

• • 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!!)

22. S-LPA 2 kW

• Old DNK 2703

• • NNO, KRU and VIL-2

• • Obsolete. No maintainable

• • K3S64D(Only possible COTS)

23. 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)

24. X-SSPA 500 W

• DNS 7703/500 from SODIELEC

• • Developed end of 90s

• • Modular

• • double preamplifier

• • Graceful degradation

25. X-LPA 2 kW

• DNK 7703 for NNO and DS3

• K3C for CPI (COTS) for CEB

• Former RSI and Vertex units already removed

26. X-HPA 20 kW

• Needs a DI cooling system

• ETM 203-X for NNO and CEB

• RhI TRA 000AA for CEB and DS3

27. De-Ionized Cooling System

• 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

28. Ka-KPA 500 W (future)

• Option for Cebreros and DS3 stations

• Ka Band uplink required for RS experiments of Bepi Colo