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Focal-plane arrays for radio astronomy; design, access and yield

Objective

1.1 Objectives:
The objective of the FARADAY project is to undertake the R&D required to produce two-dimensional receiver arrays to be installed at the foci of large radio telescopes and hence greatly to improve their observational efficiency. At the heart of the project is the design of complex monolithic microwave integrated circuits (MMICs) using levels of integration not previously employed for cryogenic applications, in the band 18-36 GHz, or for phased arrays in the 2-5 GHz band. The four sub-projects involve the design and development of:
1) Cryogenic horn arrays for continuum work in the band 26-36 GHz (main partner: University of Manchester, UK);
2) Cryogenic horn arrays for spectroscopy in the band 18-26 GHz (main partner Instituto di Radioastronomia, Bologna, Italy);
3) Non-cryogenic actively-phased arrays in the band 2-5 GHz (main partner Stichting ASTRON, Dwingeloo, The Netherlands);
4) Data acquisition hardware and transportable data analysis software for horn arrays (main partner Nicholas Copernicus University, Torun, Poland).

For each these sub-projects the contribution of the self-financing Australian partner (CSIRO/Australia Telescope National Facility, Epping, NSW ) has been, and will remain, critical to the success of the FARADAY programme. The programme and its methodology as laid out in Annex-1 have been largely followed in year 1 but with some enforced changes in strategy.

1.2 Achievements in year 1:InP MMIC designs: In the first year excellent progress has been made in the design of the InP MMIC circuits for sub-projects 1,2 and 3. A close collaboration has been achieved between the European and Australian partners and as a result the European partners have made a quantum leap in their knowledge of MMIC design using InP technology. The designs will be sent to the selected foundry (TRW/Velocium, Redondo Beach Ca.) in February 2003 for final design review prior to being made into physical circuits in the first half of 2003 with circuit testing being carried out in the second half of 2003. Passive component design for horn arrays: For sub-project 2: new ideas and experience have been gained in experimenting with dewar performance in the face of the high thermal load resulting from many receivers (in this case 10) being placed within a single large dewar. Design of compact horns (in collaboration with University of Florence/MECSA) has reduced as much as possible the dewar dimensions and hence this thermal load. Electromagnetic design of focal-plane phased-array performance: The Focal Field Distribution (FFD) appropriate for a large parabolic antenna (one of the 25m antennas of the WSRT) has been calculated using the professional antenna design program GRASP8 (in collaboration with ESTEC). Single and multi-beam performance has been investigated on the basis of an 8x9 Vivaldy-element array antenna. A densely-packed array antenna like this, whose elements are then grouped into rings with well-chosen excitation coefficients, allows one to obtain more efficient illumination patterns than a classical coaxial horn. Simulations show that, even with f/D=0.35 optics, efficient 16-beam and possibly 81-beam configurations can be achieved. Initial tests of the Vivaldi array have also been carried out with a Luneburg lens in collaboration with CSIRO/ATNF. Data Acquisition and Software design for horn arrays: TCfA staff have developed a prototype data acquisition and monitoring module consisting of an embedded Linux computer, commercial digital input/output card of the PC104 standard and a prototype data acquisition module. A TCfA software engineer has worked closely with CSIRO/ATNF on AIPS++ software for data analysis. The first new software component-a flexible image display programme (VIEWER) has been completed. A software requirements document is being finalised and a decision to base the continuum analysis software on an extension of the ATNF spectroscopic data acquisition and analysis software “LIVEDATA” has been taken.

1.3 Project Manager Information Project Coordinator: Prof. P. Wilkinson (University of Manchester)Sub-project 1: Project Coordinator: Prof. P. Wilkinson (JBO, participant 1) Project Manager : Ms. D. Kettle Sub-project 2: Project Coordinator: Prof. G. Tofani(CNR/IRA, participant 2) Project Manager : Dr. S. OrfeiSub-project 3: Project Coordinator: Mr. A. van Ardenne (ASTRON, participant 3) Project Manager : Mr. J-G Bij de Vaate Sub-project 4: Project Coordinator: Prof. A. Kus(TCfA, participant 4) Project Manager : Mr. G. PazderskiSelf-financing partner: Project Manager: Dr. W. Brouw (All sub-projects)(CSIRO/ATNF, participant 5) Management and coordination are by monthly teleconferences and face-to-face meetings held at no greater than six-monthly intervals. In year 1, three face-to-face meeting were held. Minutes of these all these meetings are available on the FARADAY web-site.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

UNIVERSITY OF MANCHESTER
Address
Oxford Road
M13 9PL Manchester
United Kingdom

Participants (4)

COMMONWEALTH SCIENTIFIC AND INDUSTRIAL RESEARCH ORGANISATION
Australia
Address
Vimiera & Pembroke Rds
Epping, Nsw
ISTITUTO NAZIONALE DI ASTROFISICA
Italy
Address
Via Del Parco Mellini 84
00136 Roma
NETHERLANDS FOUNDATION FOR RESEARCH IN ASTRONOMY
Netherlands
Address
4,Oude Hoogeveensedijk 4
7990 AA Dwingeloo
NICHOLAS COPERNICUS UNIVERSITY
Poland
Address
12/18,Ul. Chopina 12/18
87 100 Torun