PHAROS2 Phased Array Feed: Warm Section, signal transportation and iTPM digital backend A. Navarrini 1 , J. Monari 2 , A. Melis 1 , R. Concu 1 , A. Scalambra 2 , A. Maccaferri 2 , A. Cattani 2 , P. Ortu 1 , G. Naldi 2 , J. Roda 2 , F. Perini 2 , G. Comoretto 3 , M. Morsiani 2 , A. Ladu 1 , S. Rusticelli 2 , A. Mattana 2 , G. Bianchi 2 , L. Marongiu 1 , M. Schiaffino 2 , E. Carretti 1 , A. Saba 1 , F. Schillirò 4 , E. Urru 1 , G. Pupillo 2 , M. Poloni 1 , T. Pisanu 1 , R. Nesti 3 , G. Muntoni 1 , K. Zarb Adami 5,6 , A. Magro 5 , R. Chiello 6 1 INAF-Osservatorio Astronomico di Cagliari, Selargius, Italy 2 INAF-Istituto di Radioastronomia, Bologna, Italy 3 INAF-Osservatorio Astrofisico di Arcetri, Florence, Italy 4 INAF-Osservatorio Astrofisico di Catania, Catania, Italy 5 University of Malta, Malta 6 University of Oxford, Department of Physics, UK PAF2017 Workshop, Sydney, Nov. 16 th 2017
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PHAROS2 Phased Array Feed: Warm Section,
signal transportation and iTPM digital backend
A. Navarrini1, J. Monari2, A. Melis1, R. Concu1, A. Scalambra2, A. Maccaferri2, A. Cattani2, P. Ortu1,
G. Naldi2, J. Roda2, F. Perini2, G. Comoretto3, M. Morsiani2, A. Ladu1, S. Rusticelli2, A. Mattana2,
G. Bianchi2, L. Marongiu1, M. Schiaffino2, E. Carretti1, A. Saba1, F. Schillirò4, E. Urru1, G. Pupillo2,
M. Poloni1, T. Pisanu1, R. Nesti3, G. Muntoni1, K. Zarb Adami5,6, A. Magro5, R. Chiello6
1 INAF-Osservatorio Astronomico di Cagliari, Selargius, Italy 2 INAF-Istituto di Radioastronomia, Bologna, Italy
3 INAF-Osservatorio Astrofisico di Arcetri, Florence, Italy 4 INAF-Osservatorio Astrofisico di Catania, Catania, Italy
5 University of Malta, Malta 6 University of Oxford, Department of Physics, UK
PAF2017 Workshop, Sydney, Nov. 16th 2017
PHAROS System Overview
• International collaboration, FARADAY FP5 Radionet programme,
started over 10 years ago;
• Cryogenically cooled PAF with analog beamformer designed to
produce 4 synthesized beams;
• Each beam is synthesized with 13 focal plane antenna elements:
PAF2017 Workshop, Sydney, Nov. 16th 2017
PHAROS System Overview
• International collaboration, FARADAY FP5 Radionet programme,
started over 10 years ago;
• Cryogenically cooled PAF with analog beamformer designed to
produce 4 synthesized beams;
• Each beam is synthesized with 13 focal plane antenna elements:
PAF2017 Workshop, Sydney, Nov. 16th 2017
PHAROS System Overview
• International collaboration, FARADAY FP5 Radionet programme,
started over 10 years ago;
• Cryogenically cooled PAF with analog beamformer designed to
produce 4 synthesized beams;
• Each beam is synthesized with 13 focal plane antenna elements:
PAF2017 Workshop, Sydney, Nov. 16th 2017
PHAROS System Overview
• International collaboration, FARADAY FP5 Radionet programme,
started over 10 years ago;
• Cryogenically cooled PAF with analog beamformer designed to
produce 4 synthesized beams;
• Each beam is synthesized with 13 focal plane antenna elements:
PAF2017 Workshop, Sydney, Nov. 16th 2017
PHAROS System Overview
• International collaboration, FARADAY FP5 Radionet programme,
started over 10 years ago;
• Cryogenically cooled PAF with analog beamformer designed to
produce 4 synthesized beams;
• Each beam is synthesized with 13 focal plane antenna elements:
1
1
1
1
1
1
1
1
1
1
1
1
3 3
3 3
3
3
3
3
4
4
4
4
• Array of 10x11 dual-pol. Vivaldi antennas;
• Total n. of radiating elements 24 (+dummies)
in one polarization;
• Vivaldi antenna pitch is 21 mm;
• C-Band (4-8 GHz) with focus on 5-7 GHz;
PAF2017 Workshop, Sydney, Nov. 16th 2017
PHAROS
PAF2017 Workshop, Sydney, Nov. 16th 2017
PHAROS2 main specs
• Re-use some of existing PHAROS hardware;
• New cryogenic LNAs with state-of-the-art performance (from
LNF) to replace the existing ones;
• Design and possible fabrication of new radome (UMAN, Chalmers
and in-kind contribution from NRC);
• Digital backend (at room temperature) to replace existing analog
beamformer (INAF, Univ. Malta);
• Pre-filtering, amplification and downconversion: Warm Section
(INAF);
• IF over Fiber (IFoF) analog signal transportation (INAF);
PHAROS2 framework and partners
PAF2017 Workshop, Sydney, Nov. 16th 2017
• SKA Advanced Instrumentation Program on PAF;
• C-band PAF demonstrator with digital beamformer;
• Partners: INAF, UMAN, ASTRON, Chalmers Univ., Malta Univ.;
• Fast C-band continuum surveys, and polarization meas. in particular in the
Galactic Plane (to improve existing surveys to 2.5’ resolution);
(Non comprehensive) science possibilities at
C-band with cryo PAF
• High Dispersion Measure pulsar searches toward the Galactic Centre and inner
Galaxy;
• Excited rotational states of OH near 6.03 GHz: Zeeman effect, star formation;
• CH3OH (6.7 GHz): survey of methanol masers, gas kinematics, UC HII region;
• Formaldehyde line emission at 4.8 GHz;
• Flat spectra transients/pulsars, like magnetars;
• Hydrogen recombination lines around 5 GHz;
• CMB foregrounds;
• Gamma Ray Burst and Gravitational Wave event follow-ups;
• FRB search;
• Confusion limited polariz. mapping of Galaxy Clusters and Supernova Remnants;
PAF2017 Workshop, Sydney, Nov. 16th 2017
PHAROS2 more detailed specs RF range: 4.0-8.0 GHz
Frequency downconversion type: Single, with sideband separation mixer (2SB), LSB
LO frequency range: 4.650-8.375 GHz (LSB tuning)
IF frequency range: 375-650 MHz (275 MHz instantaneous bandwidth)
N. of active antenna elements: 24 (out of 220 Vivaldi antenna elements)
N. of compound beams: 4 (using 24 antenna elements)
N. of polarizations: 1 (single-polarization)
Selectable RF filters, frequency
ranges and LO tuning
frequencies:
Selection of one BPF out of four possible ones:
a) 4.0-8.0 GHz; LO tunable anywhere across 4.65-8375 GHz
b) 4.775-5.050 GHz (Formaldhyde at 4.8 GHz and H recombination
lines); LO fixed at 5425 MHz;
c) 5.78-6.055 GHz (Excited rotational states of OH near 6.003 GHz);
LO fixed at 6.43 GHz;
d) 6.445-6.720 GHz (Methanol maser line at 6.668 GHz); LO fixed at
7.095 GHz;
When options b), c) or d) are chosen the mixer image sideband rejection
is increased by the filter rejection (total expected> 40 dB);
IF signal transportation: Two IF signals transported over a single optical fiber (IFoF) using
Wavelength Division Multiplexing (1270 nm and 1330 nm)
Backend and beamforming: Digital backend with one iTPM (Italian Tile Processing Module)
capable of digitizing 32 inputs, 512 frequency channels
RFI situation at C-Band at JBO and PHAROS2 BPFs
PAF2017 Workshop, Sydney, Nov. 16th 2017
fLO(b)=5425 fLO(c)=6430
fLO(d)=7095
Schematic diagram of PHAROS2
Design of PHAROS2 Warm Section (WS)
Standard 6U rack (19”) with: 4 WS RF/IF modules, 1 LO distribution module and 3 power
supplies: handling 32 x RF input signals, 24 from cryostat + 1 calibration from noise source
(7 unused);
LO
distribution
module
3 × Power
supplies 4 WS RF/IF modules
Fiber-Ethernet
media converter
Power switch
and plug
PCB: view of layers and RF/LO/IF components: WS module:
4 laser TXs
8 x RF inputs
1 LO input
4 optical fiber outputs
PCB integrated
in mechanical
module
• One WS module has 8 x RF inputs, 1 LO input and 4 WDM IFoF outputs (4 laser OTXs);
• Single four-layer PCB with surface mount components (no bonding, easy assembly,
low-cost) inside mechanical housing. Biased with a single 5 V voltage;
• 1 LO input internally distributed with 8-way splitter (+filtering section and LO ampl.);
RF1
RF2
RF3
RF4
RF5
RF6
RF7
RF8
LO
IF1
IF2 IF3
IF4
IF5
IF6
IF7
IF8
RF5
RF2
RF3
RF1
RF4
RF6
RF7
RF8
LO
PAF2017 Workshop, Sydney, Nov. 16th 2017
Design of WS RF/IF module:
To 4 laser
OTXs
LO in = 0dBm
LO distribution chain
RF chain with BPFs, including amplifier and
mixer conversion loss
IF chain: from mixer output to optical
transmitter input
RF chain with BPFs, including amplifier and
mixer conversion loss
Electromagnetic simulation results of WS module G
ain (
dB
) G
ain (
dB
)
Gai
n (
dB
)
Gai
n (
dB
)
IF over Fiber (IFoF)
CWDM (Coarse Wavelength Division Multiplexing) for IF over fiber
technology. Developed for SKA LFAA by INAF-led collaboration:
- Two different IF signals (from two different single-pol antenna elements)
transmitted over same optical fiber using different optical carriers
at =1270 nm and =1330 nm;
- Dual laser sources and dual photodiode detectors in single packages.
- Isolation between channels: >45 dB (375-650 MHz);
- Demultiplexed at optical receiver side;
- Half FO, connectors, fusion splices, fibre joints (compared to more
standard non-multiplexed links);
- Widely used in fiber optic communication systems low cost;