Optimisation of the AA-low system

AAVP WorkshopDecember 2010 TITLE AAVP WorkshopDecember 2010 Optimization of AA-low systems

Optimisation of theOptimisation of theAA-low systemAA-low system

Cambridge 8th-10th December 2010

Jader Monari, Federico Perini, Stelio MontebugnoliGermano Bianchi, Marco Schiaffino, Giovanni Naldi, Marco Bartolini

Giuseppe Virone, Pierluigi Debernardi, Riccardo TasconeOscar Antonio Peverini, Giuseppe Addamo


SKADS – (IRA-INAF) SKADS – (IRA-INAF) AAVP WP5 AA-lo AAVP WP5 AA-lo

Experience fromSKADS-BEST

(UHF)(1400 sqm)

Experience from a VHF prototype.

(800 sqm)

AAVP(AA-lo2)

This is the point we start from….

AAVP WorkshopDecember 2010 TITLE

General Specifications about AAlo General Specifications about AAlo architecture architecture

• Face up the AAlo architecture problems:

– Reduce Costs– Reduce Complexity– Increase Reliability– Increase Maintainability

• 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......

– Very Scalable System– Modular System– Easy to replicate all parts– Design for deployment


AAlo specification AAlo specification from SKA MEMO125 / DoWfrom SKA MEMO125 / DoW


•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.

AAVP AAVP WP5 AAloWP5 AAlo

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.

Self powered FE+ Optical Link


AAVP AAVP WP5 AAloWP5 AAlo


A/DPol 1

TxPolyphaseFilter Bank

Fast Digital Link to tickData processing

Box Outdoor

RxLNA AAFilt.

Local Pre Proces.

Sync. Handl.

Shelter

Packet.

70– 450 MHz

Tx Rx AAFilt.

Cal.RFI

PolyphaseFilter Bank

A/DPol 2

Cal.RFI

Cal.RFI

Word reduction

Small Solar Panel

LNA

2x730mW

AAlo basic block diagramAAlo basic block diagram


Tx

Fast Digital Link to tickData processing

Box Outdoor

RxLNA AAFilt.

Shelter

70– 450 MHz

Tx Rx AAFilt.

A/DPol 1

PolyphaseFilter Bank

Local Pre Proces.

Sync. Handl.

Packet.

Cal. RFI

PolyphaseFilter Bank A/D

Pol 2

Cal. RFI

Cal. RFI

Word reduction

Small Solar Panel

LNA

2x730mWRx A

Rx A

Rx A

Rx A

AAlo basic block diagramAAlo basic block diagram


• 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

Technical talk Antenna Giuseppe and about the Ta calculation Federico

Antenna taskAntenna task


Ta calculator allows us to evaluate Antenna Temperature which include ground&sky contribution (preliminary results)

Considering Aeff/Tsys=2000 as MEMO 125 Specs optimized for different frequency

Number of AntennasNumber of Antennas

Ta =1757K@70MHz 113K@230MHz 70K@450MHz

3.3M

1.5M

0.96M

H Plane


Analogue VCSEL linkAnalogue VCSEL linkUltra 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 withIEIIT-CNR Turin

Pierluigi DebernardiVCSEL 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 tocompare the VCSEL links withstandard coax DFB 1300nm linksin a real environment and withreal astronomical observations.


AA-lo FE rough estimation AA-lo FE rough estimation of the power consumptionof 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

Tx

Box Outdoor

LNA AFilt.

70– 450 MHz

Wide Bandsensor

Opticalfibre

AAVP WorkshopDecember 2010 TITLE

Reliability: Electrical Field MeterReliability: Electrical Field Meter

Lightning ProtectionTransit of Storm Clouds20/06/2010 - Medicina


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.

2011 Italian AAlo plan2011 Italian AAlo plan


•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

ConclusionsConclusions


Any questions?Any questions?

Merry ChristmasMerry Christmas&&

Happy NewHappy NewYear fromYear from

Italian TeamItalian Team



4.3M

3.7M

2.45M

E Plane

Documents

Optimisation of the AA-low system