Transcript Diapositiva 1 - University of Cambridge

Optimisation of the
AA-low system
Cambridge 8th-10th December 2010
Jader Monari, Federico Perini, Stelio Montebugnoli
Germano Bianchi, Marco Schiaffino, Giovanni Naldi, Marco Bartolini
Giuseppe Virone, Pierluigi Debernardi, Riccardo Tascone
Oscar Antonio Peverini, Giuseppe Addamo
December 2010
Optimization TITLE
of AA-low systems
AAVP Workshop
SKADS – (IRA-INAF)  AAVP WP5 AA-lo
Experience from
SKADS-BEST
(UHF)
(1400 sqm)
AAVP
(AA-lo2)
Experience from
a VHF prototype.
(800 sqm)
This is the point we start from….
December 2010
Optimization TITLE
of AA-low systems
AAVP Workshop
General Specifications about AAlo
architecture
• Face up the AAlo architecture problems:
–
–
–
–
Reduce Costs
Reduce Complexity
Increase Reliability
Increase Maintainability
–
–
–
–
Very Scalable System
Modular System
Easy to replicate all parts
Design for deployment
• Study the crucials parts
– Antennas
– Minimizing the cabling from Front End to Receiver/Digital Acquistion System
........ perhaps it is worth putting a single sensor to save
money......
December 2010
TITLE
AAVP Workshop
AAlo specification
from SKA MEMO125 / DoW
December 2010
Frequency
Coverage
Inst. Bandwidth
70 – 450 MHz
System
Temperature
(@300MHz)
Array Type
120K
Sparse
Sky Coverage
Polarisations
±45°
2 linear
Tile size
No. of Tiles
64
4
380MHz
Optimization TITLE
of AA-low systems
AAVP Workshop
AAVP WP5 AAlo
•Antenna and Front End: LNA+ post amplifiers
+Analogue Optical Transmitter supplied with solar
panel.
•Digital Station: Analogue Optical RXs, Power
amplifications, ADCs, Digital boards inside a shielded
shelter. In order to reduce the digital electronic, an
analogue beamformer could be considered.
Self powered FE+ Optical Link
Galvanic isolation between FE and DS, more stable amplitude&phase Vs temperature
so easy to deploy it (not necessary to bury the FO), RFI immunity, no DC power losses
on the cable, no Gain disequalization.
December 2010
Optimization TITLE
of AA-low systems
AAVP Workshop
AAVP WP5 AAlo
December 2010
Optimization TITLE
of AA-low systems
AAVP Workshop
AAlo basic block diagram
Shelter
Sync.
Handl.
Box Outdoor
LNA
Filt.
A
70– 450 MHz
LNA
Filt.
Tx
Rx
A
A/D
Pol 1
Cal.RFI
Local
Pre Proces.
2x730mW
A
Polyphase
Filter Bank
Tx
Rx
A
A/D
Pol 2
Polyphase
Filter Bank
Cal.RFI
W
o
r
d
r
e
d
u
c
t
i
o
n
Packet
.
Small Solar Panel
December 2010
Fast Digital Link to tick
Data processing
Optimization TITLE
of AA-low systems
AAVP Workshop
AAlo basic block diagram
Shelter
Sync.
Handl.
Rx
A
Rx
A
Rx
A
Box Outdoor
LNA
Filt.
A
Tx
A/D
Pol 1
Polyphase
Filter Bank
Cal. RFI
Local
Pre Proces.
70– 450 MHz
LNA
Filt.
2x730mW
Rx
A
Tx
Rx
A
A
A/D
Pol 2
Polyphase
Filter Bank
W
o
r
d
r
e
d
u
c
t
i
o
n
Cal. RFI
Rx
A
Packet.
Small Solar Panel
Fast Digital Link to tick
Data processing
December 2010
Optimization TITLE
of AA-low systems
AAVP Workshop
Antenna task
Technical talk Antenna  Giuseppe and
about the Ta calculation  Federico
• Frequency Range: 70-450 MHz
• Dual Linear Polarization
• Maximum cross polarization at zenith < -20 dB
• Impedance Matching 50 – 75 Ohm
• Maximum length: 2 m
• Optimize the performances from 260 to 450 MHz
• Directivity has to be maximized in the scanning range from 0° to 45° (required sky coverage)
• No Balun is required to connect the LNA
• No ground plane
• Designed for deployment
December 2010
Optimization TITLE
of AA-low systems
AAVP Workshop
Number of Antennas
Ta calculator allows us to evaluate Antenna Temperature which include ground&sky
contribution (preliminary results)
Ta =1757K@70MHz 113K@230MHz 70K@450MHz
Considering Aeff/Tsys=2000 as MEMO 125 Specs optimized for different frequency
3.3M
1.5M
H Plane
0.96M
December 2010
Optimization TITLE
of AA-low systems
AAVP Workshop
Analogue VCSEL link
Ultra low cost and low power consumption devices are required for AAlo system.
In the INAF AAlo design the antenna signals are sent to a local processing node (called digital station)
through analogue optical links (70-450MHz) in the range of max 500mt (requested SFDR: 50dB
RIN=107dB/Hz2/3)
Collaboration with
IEIIT-CNR Turin
Pierluigi Debernardi
VCSEL designer
Device under investigation: 850nm (single and multi mode) and 1300nm
(single mode)
Optical fibre under investigation: multimode (62.5um, OM3 50um) and
standard single mode (9/125).
Test bed: BEST-2 and BEST-3lo systems.
This way we will be able to
compare the VCSEL links with
standard coax DFB 1300nm links
in a real environment and with
real astronomical observations.
December 2010
Optimization TITLE
of AA-low systems
AAVP Workshop
AA-lo FE rough estimation
of the power consumption
• LNA= 360mW 2 X 3V (Vds) x 60mA (Ids)
• RF Drivers = 500mW 2X 5V x 50mA
• VCSEL TX-O = 50mW 2X 3V x 8mA
Front End Total = 910mW
Wide
Band
sensor
LNA
Filt.
70– 450 MHz
December 2010
A
Tx
Optical
fibre
Box Outdoor
Optimization TITLE
of AA-low systems
AAVP Workshop
Reliability: Electrical Field Meter
Lightning Protection
Transit of Storm Clouds
20/06/2010 - Medicina
December 2010
TITLE
AAVP Workshop
2011 Italian AAlo plan
1. The IEIIT Torino group is refining the current design of the challenging 3 octaves double
polarization antenna with the required performances.
2. Extensive station simulations required and checked.
3. At IRA Mechanical construction of the designed antenna then test to verify
performances (ONE element).
4. The IEIIT /IRA group is facing the design of Analogue Optical TX-RX based on VCESEL
technology to reduce costs and power consumption.
5. IRA simulation, design and test of LNA low power matched to the designed antenna.
COTs devices will be taken into account. A complete FE will be built in order to supply it
with commercial solar panel.
6. IRA/UNIFI test of a complete Front End considering the Design for reliability.
December 2010
Optimization TITLE
of AA-low systems
AAVP Workshop
Conclusions
•International collaboration between different
group must be estabilsh to reduce efforts and
sharing expertise
•A common method to compare the different
approches should be developed
•On field tests
December 2010
Optimization TITLE
of AA-low systems
AAVP Workshop
Any questions?
Merry Christmas
&
Happy New
Year from
Italian Team
December 2010
Optimization TITLE
of AA-low systems
AAVP Workshop
December 2010
Optimization TITLE
of AA-low systems
AAVP Workshop
4.3M
E Plane
3.7M
2.45M
December 2010
Optimization TITLE
of AA-low systems
AAVP Workshop