Future Arrays for Radio Astronomy and Space Communications. Sander Weinreb. Presentation to KNI/MDL Seminar, Aug 3, 2009

Transcription

1 Future Arrays for Radio Astronomy and Space Communications Sander Weinreb Presentation to KNI/MDL Seminar, Aug 3, 2009 Square-Km Array Phased-Array Feeds Large format focal plane imaging IC development at Caltech

2 SKA Reference Design Concept Tasks at Caltech, , are the development of wideband LNA s and the integration with wideband feeds.

3 Major Science Objectives of SKA from 2009 Decadal Review

4 Square-Km Array Summary Aperture synthesis radio telescope with 1 km 2 of effective collecting area by x sensitivity, x survey speed of existing arrays Frequency range GHz; GHz in first phase Large bandwidths (4 GHz), large fields-of-view (50 deg 2 ) International funding: ~ 1.5 billion; 17- country consortium 2 short-listed sites; final selection ~ 2011; W. Australia, S. Africa Hot technology topics Phased-array feeds for wide field of view Decade bandwidth feeds and LNA s to reduce receiver cost RFI mitigation Digital transmission and processing of GHz bandwidth signals Replication cost of millions of MHz receivers and tens of thousands of 0.5 to 25 GHz receivers

5 The NASA/JPL Deep Space Network (DSN) Could Share the SKA with Radio Astronomy and Greatly Expand the Data Rate from Distant Spacecraft or Reduce the Size of a Spacecraft for a Given Data Rate. 1.E+11 1.E+10 Optical 2010 Data Rate, Bits/Second 1.E+09 1.E+08 1.E+07 1.E x 12m Array, Ka Current DSN X band 3600 x 12m 1.E+05 1.E+04 MARS JUPITER Distance, A.U.

6 SKA Program Components and Time Line SKA program comprises Low (0.1 to 0.5 GHz stationary arrays), Mid (0.3 to 10 GHz 12m reflectors), and High (1 to 50 GHz). Low and mid to be co-located in S. Africa or W. Australia Pathfinder (1%) instruments are ATA, LOFAR, ASKAP, and MeerKat Site Selection Phase 1 funding request Phase 2 funding request Phase 1 complete SKA-mid+low Complete Pathfinder implementation Pathfinder operations Early Science SKA mid+low SKA Ops Concept Design System Design US TDP Detailed Design, Prod. Eng. &Tool g Phase 1 Construction Concept design for SKA-high Full SKA mid + low construction and commissioning System design SKA-hi SKA-high Construct 26 February 2009

7 Australia SKA Pathfinder - ASKAP Well funded (~$100M US) instrument located at potential SKA site in western Australia. Under construction for completion by x 12m antennas on order from China with first antenna due. Antenna has 3 rd rotation axis to test dynamic range limitations due to beam rotation. Phased-array feed with ~100 dual-polarized elements giving ~30 beams from 0.7 to 1.8 GHz.

8 Summary of Wideband Feeds From Bradley and Gawande, URSI Meeting, Boulder, Jan 2009

9 Phased-Array Feeds Increase FOV of Radio Telescopes Mapping speed and survey speed can be increased but signal processing costs are substantial and limit bandwidth. At right, crossed-dipole feeds used for tests on 20m telescope at NRAO Green Bank Below, beam former outputs for PAF tested at 25m telescope at Westerbork. Beamwidth is ~1 o so a 36 beam area field is realized with < 50% loss. Beams that are arbitrarily close can be formed so ~170 beams could be formed with crossover at 1 db points.

10 Caltech EE Radio Astronomy Projects Wideband cryogenic InP MMIC LNA s Over 200 delivered Development of very low noise SiGe HBT LNA s MMIC receivers (IF LNA s and downconverters) for multi-pixel mmwave and sub-mm arrays Supercam U. of Arizona, 64 x 345 GHz receiver STO Stratospheric THz Observatory MMIC receivers (RF LNA s and downconverters) for large arrays Allen Telescope Array Completed GHz differential-input cryogenic LNA development in SKA Four years of development starting 2008 Wideband receivers for educational 34m radio telescope - GAVRT

11 Caltech-Developed Cryogenic LNA s 4 12K 0.5 to 11 GHz, Tn < 5K 4 to 14 GHz, Tn < 8K 6 to 20 GHz, Tn < 12K 11 to 34 GHz, Tn < 20K Over 200 LNA s supplied to other research centers GHz LNA #82D at 12K MMIC: WBA13, CIT , R8C2 Bias: Vd=1.2V, Id=20mA, Vg1=2.33V, Vg2=2.33V 50 Noise Temp(K) 6-18GHz LNA #40A03 at 12K MMIC WBA618 R7C1M0 CRYO , Bias: Vd=0.65V, Id=16mA, Vg1=1.9V, Vg2=1.9V Date : NOV Gain[dB] Noise Temperature (K) Gain (db) 40 Noise Temp(K) Noise Temperature (K) Gain (db) Gain, db Frequency (GHz) Frequency (GHz)

12 SiGe Cryogenic Low Noise Amplifier Work at Caltech Devices from several manufacturers have been measured at temperatures from 300K to 15K as part of the Ph.D. thesis of Joe Bardin. A key parameter for noise at < 5 GHz and is the current gain at 15K shown below.

13 Minimum Cascaded Noise Temperature vs Frequency and Temperature for 7 Types of SiGe Transistors Based upon measured S parameter and DC data vs temperature and shot noise model of noise. From Silicon-Germanium Heterojunction Bipolar Transistors For Extremely Low-Noise Applications, Ph.D. thesis, Caltech, June, 2009,

14 SiGe IC Cross-Section Many interconnect layers enable complex circuits 4um 4um 0.65um 0.35um 0.35um 0.35um 0.45um AM, aluminum, t=4um LY, aluminum, t=1.25um MQ, copper, t=0.55um M4, copper, t=0.32um M3, copper, t=0.32um M2, copper, t=0.32um M1, copper, t=0.29um Substrate Photo reproduced from:

15 12/04/

16 Current State-of-the-Art, 64 pixel, Millimeter Wave Camera U. of Arizona, Supercam Project

17 Caltech 4-12 GHz LNA s for Integration with 345 GHz SIS Mixers Collaboration with U. of Arizona to Develop 64 Pixel Camera LNA with cover on Input circuit including SIS bias, MMIC LNA chip, output line, and, at top, bias filter network

18 Packaging Progression Multi-Function Chip Multi-Pixel Array Wafer

19 Wafer Scale Integration of SIS/LNA/Photonic 300 GHz Spectrometer Array (from July 21, 2008 KISS Imaging Workshop) 1) Hot via interconnections 2) Needs feasibility study leading to 5 year plan 3) Alternative to photonics is miniature flexible printed-circuit ribbons 100 x 100 pixels in 5 x 5 cm Superconductor - Junctions and antenna Semiconductor IF LNA's Photonic - lasers Fiber Bundle

20 Information About 3-D Packaging See for news and conferences See for video of wafer bonding Note presentation by P. Chang-Chien, NGST, at July 21, 2008 KISS workshop Chisel open your memory stick to see stacked memory chips!

21 Spin-On s Technology development costs money. Radio astronomy does not have the funding to make fundamental changes in technology and thus relies on developments funded for applications. However a shift has occurred: Defense systems, satellite communications Wireless devices, games, internet service

22 A 3-D Packaging Commercial Spin-On! A tire-pressure sensor developed by Infineon and the Fraunhofer Institute Munich is shown below. It integrates a pressure sensor (but imagine a millimeter wave feed horn!), an RF transceiver, and a microcontroller by bump bonds and stacking.

23 GAVRT, a 34m Radio Telescope for Outreach and Science The Lewis Center for Educational Research (LCER) operates the Goldstone- Apple Valley 34m Radio Telescope, GAVRT, for use in K-12 science education. Science teachers are trained by LCER and then use the GAVRT telescope with their students through the Internet Important program principle is professional-quality instruments for scientists to interact with the educators and classrooms to generate useful science data. Successful ongoing programs are the monitoring of the time-varying radio emissions of Jupiter and the measurements of quasar scintillations. GAVRT was founded by the triumvirate of a kindergarten teacher (Rick Piercy), a radio astronomer (Mike Klein), and a member of the US Congress (Jerry Lewis). DOD and NASA have appropriated $3.2M for renovation of a second 34m telescope, DSS28, and development of a state-of-the-art radiometer system. Caltech has been contracted to develop a 0.5 to 14 GHz radiometer system.