RF Technologies for Space Applications Oscar A. Peverini

SATCOM research activities @ CNR-IEIIT RF Technologies for Space Applications Oscar A. Peverini

Introduction Development of radio-frequency antenna-feed systems for satellite applications in the framework of a long-lasting research collaboration between CNR-IEIIT and Thales Alenia Space Italia (Space Antennas RF Design Unit - Competence Centre Electronics) Corrugated and high-efficiency feed-horns operating from Ku band to Q-band ( A Ku-K Dual-Band Compact Circular Corrugated Horn for Satellite Communications, IEEE Antennas and Wireless Propag. Letters, 2009) Self-diplexing ortho-mode transducers operating from C-band to Q band ( Modeling, Design and Experimental Characterization of Multi-band Dual-polarization Waveguide Components for Space Feed-systems, 33rd ESA Antenna Workshop, 2011) Diplexers & filters for high-power applications ( Enhanced Topology of E -Plane Resonators for High-Power Satellite Applications, IEEE Trans. on Microw. Theory and Techn., 2015) Antenna-feed systems for Athena-Fidus, Sicral-2, commercial SatCom payloads ( A K/Ka/EHF feed chain for dual-use telecom, EuCAP 2015)

1. Telecommunications Fixed Satellite Services (FSS) Mobile Satellite Services (MSS) (Iridium, Iridium-Next) Broadcasting Satellite Services (BSS) Internet, multi-media applications, Voice over IP (VoIP), Video conference (KaSAT) Military and governmental telecommunication services (e.g., civil security, homeland security, police, firefighters) (Athena-Fidus). 2. Observation of the Earth Meteorology (MetOp, MetOp-SG) Oceanography Environmental disaster monitoring, seismic hazard analysis (COSMO-SkyMed) 3. Navigation and Localization GPS Galileo 4. Cosmology and Fundamental Phisics Astrophysical surveys (Planck, WMAP) 5. Space Exploration Planet exploration (ExoMars) Satellite Missions

Satcom Networks High-Throughput Satellite (HTS) network HTS Satellite Gateways Servers Users Terminals Satellite Operator Center Backbone network PoP Internet Content Providers NOC

SatCom Frequency Bands Band Frequency (GHz) L 1.45 1.67 Service Tele/radio broadcasting, mobile services Atmospheric attenuation S 1.97 2.69 Tele/radio broadcasting to mobiles C 3.4 7.0 Tele/radio broadcasting, Internet X 7.2 8.4 Mobile services Ku 10.7 14.5 Tele/radio broadcasting, Internet K 17.7 21.2 Ka 27.5 31.2 Internet, VoIP, video conference and others IP applications Internet, VoIP, video conference and others IP applications

SatCom Frequency Bands Band Frequency (GHz) L 1.45 1.67 Service Tele/radio broadcasting, mobile services Atmospheric attenuation S 1.97 2.69 Tele/radio broadcasting to mobiles C 3.4 7.0 Tele/radio broadcasting, Internet X 7.2 8.4 Mobile services Ku 10.7 14.5 Tele/radio broadcasting, Internet K 17.7 21.2 Ka 27.5 31.2 Q 37.5 45.5 V 47.2 51.4 Internet, VoIP, video conference and others IP applications Internet, VoIP, video conference and others IP applications Feeder links for HTS (1 Tbps)

SatCom Frequency Bands Band Frequency (GHz) L 1.45 1.67 Service Tele/radio broadcasting, mobile services S 1.97 2.69 Tele/radio broadcasting to mobiles C 3.4 7.0 Tele/radio broadcasting, Internet X 7.2 8.4 Mobile services Ku 10.7 14.5 Tele/radio broadcasting, Internet Channel modelling and measurement activities (Alphasat experiment) Channel effect mitigation techniques Space diversity gateway architecture K 17.7 21.2 Ka 27.5 31.2 Q 37.5 45.5 V 47.2 51.4 Internet, VoIP, video conference and others IP applications Internet, VoIP, video conference and others IP applications Feeder links for HTS (1 Tbps)

Large Single-Beam Single-Band Antennas Ku Tx Ku Rx K Tx Different singleband antennafeed systems

Large Single-Beam Single-Band Antennas Ku Tx Ku Rx Antenna-feed systems electrical requirements Different singleband antennafeed systems K Tx Parameters Ku Tx Band Ku Rx Band K Tx Band Operative Band (GHz) 10.7 12.75 13.0 14.5 17.7 21.2 Polarization and Versus HP&VP HP&VP LHCP/RHCP Thermal bandwidth 35/50 MHz @ each band side Cross Polarisation -40 db -40 db -40 db Return Loss (VSWR) -20 db -20 db -20 db Ports Isolation (any port, any band ) > 60 db > 60 db > 60 db Number of Ports 2 2 2 Waveguide WR75 WR75 WR51 Power Handling 10 carriers x 110 W (for each pol.) N.A. 4 x 110W (for each pol.) Multipaction Intermodulation Product Level Free + 6 db margin N.A. <-140 dbm@ (2x 120 W carriers) Free + 6 db margin Minimum IMP order 3rd 16th

Large Single-Beam Single-Band Antennas Ku Tx Ku Rx Different singleband antennafeed systems K Tx Ku Tx-band dual-linear antenna-feed system Feed-horn OMT PBF PBF Ku-band Tx V-pol. signals Ku-band Tx H-pol. signals

Large Single-Beam Single-Band Antennas Ku Tx Ku Rx Different singleband antennafeed systems K Tx Ku Rx-band dual-linear antenna-feed system Feed-horn OMT PBF PBF Ku-band Rx V-pol. signals Ku-band Rx H-pol. signals

Large Single-Beam Single-Band Antennas Ku Tx Ku Rx Different singleband antennafeed systems K Tx K Tx-band dual-circular antenna-feed system Feed-horn OMT Hybrid coupler PBF PBF K-band Tx RHCP signals K-band Tx LHCP signals

Large Single-Beam Single-Band Antennas Ku Tx Ku Rx Different singleband antennafeed systems K Tx Pros Low RF system complexity High RF performances Cross-polarization Radiation-pattern Isolation Power-handling (PIMP, multipaction)

Large Single-Beam Multi-Band Antennas Ku Tx Ku Rx K Tx One multi-band antenna-feed system

Large Single-Beam Multi-Band Antennas Ku Tx Ku Rx K Tx One multi-band antenna-feed system Pros Higher capacity Lower number of reflectors (less stringent mass and size requirements)

Large Single-Beam Multi-Band Antennas Ku Tx Ku Rx K Tx One multi-band antenna-feed system Pros Higher capacity Lower number of reflectors (less stringent mass and size requirements) Cons Demanding high-power handling requirements (PIMP, multipaction) Higher RF system complexity

Large Single-Beam Multi-Band Antennas Ku Tx Ku Rx K Tx One multi-band antenna-feed system Tri-band dual-polarization antenna-feed system K-band Tx RHCP signals K-band Tx LHCP signals Ku-band Tx V-pol. signals Ku-band Rx V-pol. signals Hybrid coupler Ku-band diplexer Wide-band feed-horn K-band OMJ Dual-polarization LPF Ku-band OMT Ku-band diplexer Ku-band Tx H-pol. signals Ku-band Rx H-pol. signals

Ku/K-band Antenna-Feed System Ku/K-band antenna-feed system developed in collaboration with Thales Alenia Space Italia

Ku/K-band Antenna-Feed System K-band 90 hybrid K-band combiners Bread-board Ku-band OMT Ku/K-band self-diplexing OMT Ku/K-band feed-horn Courtesy of Thales Alenia Space Italia

Magnitude [db] -5-10 -15 Reflection coefficient Measured Computed Ku/K-band Antenna-Feed System -20-25 -30 Ku-band K-band -35-40 66 % X -45 12 14 16 18 20 Frequency [GHz] K-band 90 hybrid K-band combiners Bread-board Ku-band OMT Ku/K-band self-diplexing OMT Ku/K-band feed-horn Courtesy of Thales Alenia Space Italia

Magnitude [db] -20-25 Cross-polar radiation Measured Computed Ku/K-band Antenna-Feed System -30-35 Ku-band K-band X -40-45 66 % -50 12 14 16 18 20 f [GHz] K-band 90 hybrid K-band combiners Bread-board Ku-band OMT Ku/K-band self-diplexing OMT Ku/K-band feed-horn Courtesy of Thales Alenia Space Italia

magnitude [db] 0 K-band rejection -10-20 -30 Computed Measured (V-pol.) Measured (H-pol.) -40-50 -60-70 -80-90 18 19 20 21 f [GHz] K-band 90 hybrid K-band combiners Ku/K-band Antenna-Feed System X Bread-board Ku-band OMT Ku/K-band self-diplexing OMT Ku/K-band feed-horn Courtesy of Thales Alenia Space Italia

magnitude [db] 0 K-band cross-polarization -10-20 -30 Cross-coupling (V-pol.) Cross-coupling (H-pol.) Isolation X -40-50 -60 X -70-80 Ku/K-band Antenna-Feed System -90 18 19 20 21 f [GHz] K-band 90 hybrid K-band combiners Bread-board Ku-band OMT Ku/K-band self-diplexing OMT Ku/K-band feed-horn Courtesy of Thales Alenia Space Italia

Ku/K-band Antenna-Feed System Flight model Courtesy of Thales Alenia Space Italia

K/Ka/Q-band Antenna-Feed System K Tx Ka Rx Q Rx ATHENA-FIDUS

K/Ka/Q-band Antenna-Feed System K Tx Ka Rx Q Rx Antenna-feed system electrical requirements Parameters K Tx Band Ka Rx Band Q Rx Band Operative Band (GHz) 19.4 21.2 29.2 31.0 43.5 44.0 ATHENA-FIDUS Polarization and Versus LHCP & RHCP LHCP & RHCP LHCP & RHCP Radiation pattern Gaussian within 17.6 Cross Polarisation -30 db -30 db -20 db Return Loss (VSWR) -20 db -20 db -20 db Ports Isolation (any port, any band ) > 40 db > 40 db > 40 db Number of Ports 2 2 2 Waveguide WR75 WR75 WR51 Power Handling 4 carriers x 40 W (for each pol.) N.A. N.A. Multipaction Intermodulation Product Level Free + 6 db margin N.A. <-125 dbm@ (2x 120 W carriers) Free + 8 db margin <-125 dbm@ (2x 120 W carriers) Minimum IMP order N.A. 4th 11th

Ku/K-band Antenna-Feed System K Tx Ka Rx Q Rx K/Ka/Q-band antenna-feed system developed in collaboration with Thales Alenia Space Italia ATHENA-FIDUS K-band Tx RHCP signals K-band Tx LHCP signals Ka-band Rx LHCP signals Hybrid coupler Wide-band feed-horn K-band OMJ K-band SBF Q-band OMJ Q-band SBF Ka-band septum polarizer Hybrid coupler Ka-band Rx RHCP signals Q-band Rx RHCP signals Q-band Rx LHCP signals

Ku/K-band Antenna-Feed System Flight model K Tx ports (LHCP/RHCP) Ka Rx ports (LHCP/RHCP) Q-band Rx port (LHCP) Courtesy of Thales Alenia Space Italia

Multi-Spot SFB Antennas K/Ka K/Ka K/Ka K/Ka Multi-spot Single-Feed per Beam (SFB) architectures Frequency reuse A dedicated feed-system per each spot (typical diameter 0.5o ) Overlapping spots Band Polarization B1 RHCP LHCP B1

Multi-Spot Dual-Band SFB Antennas K/Ka K/Ka K/Ka K/Ka Pros Capacity increment proportional to the frequency reuse factor (number of spot / number of colors) No additional power requirements

Multi-Spot Dual-Band SFB Antennas K/Ka K/Ka K/Ka K/Ka Pros Capacity increment proportional to the frequency reuse factor (number of spot / number of colors) No additional power requirements Cons Higher RF system complexity Demanding pointing accuracy (closedloop auto-alignment systems based on beacon tracking)

Magnitude [db] Dual-Band SFB Feed-Systems In-line compact assembly Wide-band feed-horn Ka-band OMJ Dual-polarization Ka-band SBF K-band OMT HF hybrid + diplexers High-efficiency horn Tracking sub-system D-mode HF Rx signal for tracking K-band Tx signals K-band Rx signals 0 Radiation patterns @ 28 GHz Frequency 28.0 GHz K/Ka-band antenna-feed system design study in collaboration with Thales Alenia Space Italia -2-4 -6-8 -10-12 -14-16 -18 V rx TE eq 11 V rx eq TM 01 V rx TE eq 21-20 -20-15 -10-5 0 5 10 15 20 Theta [deg]

(db) S 11 (db) S 11 (db) Dual-Band SFB Feed-Systems -20-25 Reflection coefficient @ K band Measurement Simulation -30 Courtesy of Thales Alenia Space Italia -35 0-10 -20-30 Radiation patterns @ 29 GHz frequency =29.0 GHz Co-Sim Co-Meas Xp-Sim Xp-Meas -40 19 19.2 19.4 19.6 19.8 20 20.2 20.4 20.6 Frequency (GHz) -20-25 Reflection coefficient @ Ka band Measurement Simulation -40-50 -60 0 5 10 15 20 25 30 35 40 Theta (deg) -30-35 -40 29 29.5 30 30.5 Frequency (GHz)

Additive Manufacturing of RF Components Selective Laser Melting Pros Manufacturing of parts with complex geometries integration of several RF functionalities in a single block, minimization of flanges and screws (e.g. SFB and MFB satellite communication systems) Design flexibility novel layouts of waveguide components Near-net shapes reduction of mass and waste Reduction of lead time and cost more efficient component development Cons Manufacturing accuracy and repeatability poor RF performance @ high frequencies (Ka, Q bands) Maximum part size no applicability to low frequency applications (C, X bands) Surface roughness high insertion losses

Additive Manufacturing of RF Components Additive manufacturing of K/Ku-band filters for SatCom applications in collaboration with the Italian Institute of Technology

Additive Manufacturing of RF Components Thanks for your attention