ESA ANTENNA WORKSHOP ON MULTIPLE BEAMS AND RECONFIGURABLE ANTENNAS,
18-20 APRIL 2007
Experience with sparse arrays at the University of Oslo
Sverre Holm, Andreas Austeng, Jan Egil KirkebÝ,
Department of Informatics, University of Oslo, P.O. Box 1080, NO-0316 Oslo, Norway
Email: Sverre.holm( at) ifi.uio.no
This paper gives an overview over work on layout and weight optimization of sparse 1D and 2D arrays which has been
done over the last decade. The optimization methods have been linear programming, genetic methods and simulated
annealing. The latter is our preferred method. The paper shows examples of optimized arrays on Cartesian and non-
Cartesian grids such as polar and hex. Non-planar arrays (curved and cylindrical) have also been optimized.
We have been working for more than a decade on optimizing the layout of thinned arrays. We have been optimizing
symmetric 1D and 2D planar arrays and curved and cylindrical arrays. Most of our problems have involved binary
weights, i.e. elements that are either in or out, but in some cases weighting functions have been found also.
Our applications have primarily been monostatic systems for use in medical ultrasound and sonar. In imaging systems,
it is often been possible to take advantage of different array layouts for transmission and reception. These methods have
also been tested experimentally.
Our work now is concerned with geometries where elements are not aligned on a regular grid, and on optimization