New Trends on Receivers Development" May 30, 2005, Medicina. RECEIVING SYSTEMs for the ANTENNAS OPERATED by the INSTITUTE of RADIOASTRONOMY in ITALY

Transcription

1 New Trends on Receivers Development" May 30, 2005, Medicina RECEIVING SYSTEMs for the ANTENNAS OPERATED by the INSTITUTE of RADIOASTRONOMY in ITALY Alessandro Orfei IRA-INAF, Medicina station (Italy) RADIONET Receivers Workshop May 30,

2 TALK DESCRIPTION THE EXISTING RECEIVERs NEW OBSERVING GOALs CALL for UPDATED RECEIVING SYSTEMs THE UPGRADE of EXISTING ANTENNAs TOWARD 100GHz THE CHALLENGE of the NEW SARDINIA RADIOTELESCOPE (SRT) THE FARADAY PROJECT OPPORTUNITY RADIONET Receivers Workshop May 30,

3 The IRA s ANTENNAs Northern Cross (1964, 610x564m) Sardinia Radio Telescope (Cagliari), 64m Medicina(1983) and Noto(1988), 32m RADIONET Receivers Workshop May 30,

4 PARABOLIC DISHEs CHARACTERISTICS DIAMETER = 32m CONFIGURATION = CLASSIC PARABOLIC\HYPERBOLIC TWO FOCI AVAILABLE FOR PLACING RECEIVERs f1/d = 0.32; f2/d = 3 TOTAL SURFACE RMS Medicina 0.6mm TOTAL SURFACE RMS Noto 0.3mm MAX ANTENNA EFFICIENCY 60% ORIGINAL DESIGN PROVIDED fmax 22GHz (@ λmin/20) MAX RMS DEFORMATION DUE TO GRAVITY 0.6mm RADIONET Receivers Workshop May 30,

5 THE EXISTING RECEIVERs on the ANTENNAs MHz NOTO LCP+RCP GHz NOTO LCP+RCP / GHz MEDICINA LCP+RCP/LCP+RCP / GHz NOTO RCP/RCP / GHz MEDICINA LCP+RCP/LCP+RCP / GHz NOTO LCP+RCP/LCP+RCP GHz NOTO and MEDICINA LCP+RCP 6-7GHz NOTO and MEDICINA LCP+RCP GHz NOTO H+V GHz NOTO LCP+RCP GHz MEDICINA LCP+RCP 40-50GHz NOTO LCP+RCP = after the active surface was available RF BW 20% at the most TARGETED RECEIVERs RADIONET Receivers Workshop May 30,

6 THE EXISTING RECEIVERs L/SX(coax) BANDs X/Ka BANDs coax L/SX(coax)/K BANDs Q BAND C BAND RADIONET Receivers Workshop May 30,

7 RECEIVERs NEW OBSERVING GOALs CALL for UPDATED RECEIVING SYSTEMs FREQUENCY AGILITY UPGRADED PERFORMANCE HIGHER FREQUENCIEs DIFFERENT RECEIVER SCHEMEs RECEIVERs Change in a few min. by clicking a mouse Observing days/scheduled days = 1! Number of changing more than doubled Number of Geo observation = tripled Reliability Safety at work RADIONET Receivers Workshop May 30,

8 RADIONET Receivers Workshop May 30,

9 THE UPGRADE of NOTO TOWARD 100GHz Efficiency(%) Noto32GHz:Antenna Efficiency with active surface DISABLED (Aug. 2002) Elevation (degree) Noto32GHz: Antenna Efficiency with active surface ENABLED (Aug. 2002) A TEST AT 86GHz IS PLANNED + MORE ACCURATE PANELS Efficiency(%) Elevation (degree) Antenna Efficiency (%) 43GHz A.S. DISABLED Elevation (degree) Antenna Efficiency (%) GHz A.S. enabled and also correcting subreflector surface Elevation (degree) RADIONET Receivers Workshop May 30,

10 FACING WITH DIFFERENT RECEIVER SCHEMEs 1. CLASSICAL HETERODYNE Return loss Insertion loss Crosspol Isolation Return loss Gain White Noise 1/f Noise Gain IPn Noise Radiation FEED SYSTEM LNA DOWN CONVERSIONs + FIBER OPTIC LINK IFs to Back-end T 20K NOISE CAL SIGNAL Coupling value Coupling Flatness Directivity Crosspol RADIONET Receivers Workshop May 30,

11 FACING WITH DIFFERENT RECEIVER SCHEMEs 2. DIRECT DETECTION Return loss Insertion loss Crosspol Spurious pol. Return loss Gain White Noise 1/f Noise Gain Noise Spurious pol. Radiation FEED SYSTEM LNA RF ANALOG PROCESSOR + DETECTION DC signals to A/D T 20 or 70K NOISE CAL SIGNAL Coupling value Coupling Flatness Directivity Crosspol EXAMPLEs: -Very Wide Band Total Power Detection -Correlation Radiometers RADIONET Receivers Workshop May 30,

12 .. 2. DIRECT DETECTION Phase Switch Hot LNA A Filter Direct. coupler P Total Power Detection Integr. Q Antenna Filter LNA LHP Polarizer OMT RHP LNA Reference Hybrid Phase Discriminator C C C C Reference Sync. Detect. Filter Filter Filter Phase Switch Hot LNA B FL HPD Filter Direct. coupler P Reference Total Power Detection Sync. Detect. Integr. U RADIONET Receivers Workshop May 30,

13 NON COMMERCIAL COMPONENTs for DIRECT DETECTION (32GHz CORRELATION RADIOMETER) Courtesy: IEIIT-CNR Courtesy: IEIIT-CNR Courtesy: IEIIT-CNR Courtesy: IEIIT-CNR Courtesy: IEIIT-CNR SEE PEVERINI s PRESENTATION and MACCULI s POSTER RADIONET Receivers Workshop May 30,

14 CONTINUE SEE CARRETTI s POSTER A COLLABORATION of: IASF-INAF IRA-INAF IEIIT-CNR MILANO UNIVERSITY WITHIN the SPOrt and BaR-SPOrt PROJECTs RADIONET Receivers Workshop May 30,

15 THE CHALLENGE of the SARDINIA RADIO TELESCOPE SRT RADIOFREQUENCY CHARACTERISTICs: DIAMETER = 64m SHAPED GREGORIAN OPTICS FOUR FOCI AVAILABLE FOR PLACING RECEIVERs f1/d = 0.33; f2/d = 2.34; f3/d = 1.38; f4/d = 2.81 TOTAL SURFACE RMS 0.19mm (PHASE 1); 0.12mm (PHASE 2) MAX ANTENNA EFFICIENCY 61% MAX RMS DEFORMATION DUE TO GRAVITY 0.6mm ACTIVE SURFACE (1116 ACTUATORs) RE-CONFIGURABLE MIRROR PROFILE (Shaped Parabolic) RADIONET Receivers Workshop May 30,

16 SRT: 4 FOCAL POSITIONS F4 F1 F2 F3 8 RX locations F2 F3 F1 F4 2+2 RX locations About 8 RX locations RADIONET Receivers Workshop May 30,

17 SRT:DESIGN CONSTRAINTS FOR THE RECEIVING SYSTEM FREQUENCY COVERAGE 300MHz to 100GHz (Continuous Coverage) VARIOUS FEED ORGANIZATION Mono-, Dual-, Multi-feed, Dual Frequency FREQUENCY AGILITY RX changing Automatically and in a few Minutes at the most ROBUST RX w.r.t INTERFERENCES Careful design in term of intermodulation PERFORMANCE State of the art. Allow for possible different receiver schemes. RADIONET Receivers Workshop May 30,

18 SRT: EFFECTS OF THE CONSTRAINTS Continuous coverage+finite number of RX locations+frequency agility imply: RXs WITH BROAD RF Bandwidth 35% (previous experience BW 5to20%) Requested performances imply: a) To be provided in a BROAD RF Bandwidth b) WIDE IF Bandwidth (2GHz) (previous experience 400MHz) Multifeed world implies: a) Routing Tens of IFs with BROAD BW of MOVABLE boxes b) Mechanical de-rotation of the off axis beams c) Crowded receiver RADIONET Receivers Workshop May 30,

19 λ (cm) FLow sky (GHz) FROM THE CONSTRAINTS: SRT RXs TABLE FHigh sky (GHz) BW (GHz) BW (%) Note Focus Position Dual Primary fre que ncy Dua l fre que ncy BWG Monofeed Gregorian Multife e d Down to 1.4GHz Up to 32GHz and MORE RADIONET Receivers Workshop May 30,

20 SRT:RXs SYSTEM PERFORMANCE ESTIMATE λ (cm) FLow sky (GHz) FHigh sky (GHz) RADIONET Receivers Workshop May 30, Tric (K) Tsys (K) El=45 o max IFbw (MHz) x

21 GOAL PERFORMANCE Insertion loss dB Noise 20K) 1 o K/GHz Return loss -26 db Return loss -10 db Cross-polarisation -35 db Gain db Feed System LNA Noise Best effort OIP3 > 30 dbm Cross-polarisation -35 db Receiver RADIONET Receivers Workshop May 30,

22 SOME ACHIEVEMENTs: MONOFEED GHz Riflessione [db] PORTE WR187 dell'omt porta SIDE porta IN-LINE Files: side_acc_1.txt in_line_acc_1.txt COMPLETE FEED SYSTEM Frequenza [GHz] Insertion Loss = 0.11dB RADIONET Receivers Workshop May 30,

23 .CONTINUE Riflessione [db] Return Loss modo TE11 Porta 1 Porta 2 File: finestragoffb.txt Frequenza [GHz] Trasmissione [db] Insertion Loss File: finestragoffb.txt Frequenza [GHz] PORTA 2 Styrodur3035 PORTA 1 Kapton, 25μm RADIONET Receivers Workshop May 30,

24 .CONTINUE Diagrammi normalizzati [db] Diagrammi normalizzati [db] File: 5e05_circ_azimut.txt Piano orizzontale (f=5.05 GHz) co-polare (misura) -55 cross-polare (misura) ϑ [deg] COMPLETE FEED SYSTEM File: 5e05_circ_elev.txt Piano verticale (f=5.05 GHz) co-polare (misura) -55 cross-polare (misura) ϑ [deg] Cross-polare [db] CROSSPOL EASILY IMPROVABLE: ROTATE 90 o VLBI Files: para_goff_d.txt perp_goff_d.txt circ_circ_nc_f1.txt circ_circ_c_f1.txt Frequenza [GHz] RADIONET Receivers Workshop May 30,

25 .CONTINUE PORTA 2 PORTA 5 PORTA 3 PORTA 4 PORTA 1 Trasmissione [db] PORTE WR187 dell'omt trasmissione tra la porta side e la porta in-line The OMT alone is 55dB! File: omt_1.txt Frequenza [GHz] Frequenza [GHz] RADIONET Receivers Workshop May 30, Trasmissione [db] Trasmissione tra l'accoppiatore e l'omt OMT: SIDE OMT: IN-LINE Files: side_acc_1.txt in_line_acc_1.txt

26 THE FARADAY PROJECT OPPORTUNITY FOCAL-PLANE ARRAYs for RADIO ASTRONOMY, DESIGN ACCESS and YIELD FARADAY is a collaboration between - Jodrell Bank Observatory (University of Manchester, UK), - Istituto di Radioastronomia (formerly CNR, now INAF; Italy), - Stichting ASTRON (The Netherlands), - Torun Centre for Radio Astronomy (N. Copernicus University, Poland) and the -CSIRO's Australia Telescope National Facility. FARADAY is funded by the European Commission as a FP5-RTD programme. Duration: Nov2001 to Nov months no cost extension. RADIONET Receivers Workshop May 30,

27 THE FARADAY SUBPROJECT 2: MULTIFEED 18-26GHz 14 CHANNELs, 7LCP + 7RCP 7 FEED SYSTEM + 14LNAs 20K HORN COUPLER POLARIZER 14 WARM LNAs WIDE IF BW (2GHz x 14) 4 SELECTABLE IF FILTERs (150, 450, 1000, 2100MHz wide) EXPANDABILITY for FULL BAND USE F.O. LINK INCLUDED IN THE DESIGN MECHANICAL DE-ROTATOR USABLE for SPECTROSCOPY, CONTINUUM,VLBI on SRT OMT MMIC LNA DEWAR IF CHAIN SEE POSTER and NESTI s PRESENTATION RADIONET Receivers Workshop May 30,

28 FACILITIES for RECEIVERs FEED LNA Directional coupler FULL BAND RECEIVER, BW > 2GHz SELECTABLE IFs FILTERS BW=150,450,1000,2100 MHz MAIN RECEIVER, BW = 2x2GHz FULL BAND RECEIVER OPTION: CLASSICAL + DD Tx WIDE BAND FIBER OPTIC ANALOG LINK PROs: WIDE BW MHz HIGH OIP3 (+40dBm) CONs: HIGH NF RADIONET Receivers Workshop May 30,

29 A DUAL FREQUENCY for SRT: MHz/ GHz GOAL: OBSERVING the TWO FREQUENCIES at the SAME TIME with the BEST SENSITIVITY ACHIEVABLE (PULSAR RESEARCH) STEP 1: FEASIBILITY STUDY FOR FEEDs ARRANGEMENT a) HORN for L BAND + DIPOLES for P BAND b) HORN (COAXIAL) for L and P BAND STEP 2: SEARCHING FOR BEST COMPROMISE FOR COOLING SEE POSTER RADIONET Receivers Workshop May 30,

30 CONCLUSIONS SOME CONCEPTS about RECEIVERs for RADIOASTRONOMY: RF BROADBAND ( 35%?) WITH HIGH PERFORMANCE CONTINUOUS FREQUENCY COVERAGE FAST, REMOTE and AUTOMATIC SWITCHING RECEIVERs with EXPANDABLE SCHEME LARGE BANDWIDTHs to BACK-ENDs CROWDED RECEIVERs (MULTIFEED ERA) RADIONET Receivers Workshop May 30,