The Thousand Element Array

The international radio astronomy community is currently making detailed plans for the development of a new radio telescope: the Square Kilometer Array Interferometer (SKA). This instrument will be a hundred times more sensitive than telescopes currently in use. One of the options of this new telescope is to use phased arrays with over one million receiving elements with a mixed RF/digital adaptive beamformer. THEA (Thousand Element Array) is one of the demonstrator systems that was build during the SKA development program and is continued as THEP (THEA Experimental Platform).

THEP is an out-door phased array system with 256 broadband receiving antenna elements. Beamsteering is done by a combination of RF and digital beamforming. THEP is able to make multiple beams over the sky simultaneously. In addition, adaptive beamforming may be applied to suppress EMI sources. THEP will also be used for educational purposes and for simple experiments concerning the phased array technique.

The image shows the four THEA tiles, with the radome (cover) removed, pictured with the Dwingeloo telescope at the background. One THEA tile consists of 64 wide-band antenna elements and can be used to detect (strong) radio sources in the frequency band from 600 to 1700 MHz in the presence of strong interfering RF signals.

First results

• GPS Satellite detection (May 2002) (10Mbyte)
• First Astronomical THEA Fringes (March 2003)
• Worlds first full sky dynamic 24 hour HI survey (April 2003, 4-tile resolution!!) (0.5Mbyte)

More pictures

• 16 Tiles at the outside test range
• The inside of the tile
• The antenna beamformer

Publications

• E E M Woestenburg, K F Dijkstra, "Noise characterization of a phased array tile", European Microwave Conference, Munich, Oct. 2003
• J G Bij de Vaate, S J Wijnholds, J D Bregman, "Two Dimensional 256 Element Phased Array System for Radio Astronomy", Phased Array Systems and Technology 2003, Boston, Oct. 2003
• J G Bij de Vaate, G W Kant, "The Phased Array Approach to SKA, Results of a Demonstrator Project", European Microwave Conference, Milaan, Sept. 2002
• S van de Tol, A J Boonstra, J G Bij de Vaate, A van Ardenne "Multiple satellite detection with a prototype new generation phased array radio telescope", ESA Antenna workshop, Noordwijk, Sept. 2002
• J G Bij de Vaate, G W Kant, W A van Cappellen, S. van der Tol, "First Celestial Measurement Results of the Thousand Element Array", URSI GA, Maastricht, August 2002
• S Alliot, "Adaptive Weight Estimation for Interference Nulling on a DSP", CTIT Workshop: The Challlenge of Embedded Systems, Enschede, June, 2002
• G A Hampson, J G Bij de Vaate, "Verification of THEA Tile Calibration and Beamforming Results using a Near Field Scanner", European Microwave Conference, London, Sept. 2001
• G A Hampson, J G Bij de Vaate, "Initial Calibration and Beamforming Results from the Thousand Element Phased-Array", APS, Boston, July 2001
• B Smolders, J G Bij de Vaate, G W Kant, A van Ardenn, D Schaubert, T H Chio, "Dual-beam Wide-band Beamformer with Integrated Antenna Array", APS, Davos, April 2000
• G.W. Kant, A.W. Gunst, A.B.J. Kokkeler, A.B. Smolders, "Receiver Architectures of the Thousand Element Array (THEA)", SPIE conference, Munchen, March 2000

• More publications: SKA R&D publications

For more information, please contact vaate [at] astron [dot] nl