The ASTRON Antenna Group focuses on the research and development of antennas for low noise array receiving systems. Array technology is considered an essential component to enable the next generation of radio-telescopes and is applied in aperture array and focal plane array based systems. Currently the feasibility and competitiveness of these technologies as front-ends for the SKA is being demonstrated. The Antenna Group delivers the knowledge and resources to develop and characterize these array systems. This is broader than just the antenna as critical system characteristics like the system temperature and effective area are largely determined by the antenna in combination with the low noise amplifier (LNA) and beamformer. Hence strong links exists between the Antenna Group and the RF & Low Noise Systems Group.
The Antenna Group is collaborating with several universities to commonly research the fundamental properties of antenna arrays and their application: Chalmers University (Sweden), Brigham Young University (US), Eindhoven University of Technology (Netherlands), Penn State (US), UCL (Belgium), UMass Amherst (US).
|Electromagnetic modeling: An accurate and fast prediction of the antenna characteristics is essential for designing array antennas. CAESAR is an in-house developed software tool, which is tailored to analyze large antenna array systems using only a limited amount of computational resources. State-of-the-Art modeling techniques are implemented, and novel methods are developed to continuously enhance the capabilities and computational efficiency/accuracy of the solver. CAESAR can be used to analyze quasi-static field problems, as well as electrodynamic field problems. A mixed signal- and noise analysis can be carried out for the microwave circuits, the external antenna environment, and a compound of system components. This enables one to perform sensitivity studies for radio astronomy while using realistically complex receiver models. CAESAR is available to SKADS partners and is being used by UMan and Yebes.|
Antenna System Modeling: The mutual coupling between antenna array elements necessitate higher level performance modeling of the antenna arrays in combination with the LNA and beamformer. This provides insight in the mechanisms that determine the system performance and gives grips for the antenna and LNA design, characterization, calculation of weighting coefficients and development of calibration algorithms.
Low cost antenna development: Very wideband array antennas are being designed for various projects. The tapered slot or Vivaldi element proved to be an excellent radiator for this purpose. There is special attention for the cost of aperture array tiles as this needs to be further reduced. Antenna arrays, connections, and transmission lines need to be developed and tested using low-cost production techniques and materials. These materials and processes typically have higher losses, inhomogeneities and larger tolerances. The Antenna Group is involved in the electromagnetic design and characterization of low-cost antenna concepts.
|Characterisation: Near-field scanner in anechoic chamber ASTRON has several facilities for antenna characterization and testing: anechoic chambers, a planar near-field scanner, network analyzers and an outdoor measurement platform.|