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Phased array antenna systems are a defining technology in many current and planned radio astronomical instruments. Phased array technology enables new observing modes due to their large field-of-view, multi-beaming capability and rapid response. The radio astronomical application provides interesting challenges such as stringent requirements on system temperature and system calibration. In this paper,...
Polarization purity is one of the most stringent requirements for future radio telescopes. To evaluate polarization ratio levels of large phased arrays involving thousands of elements, a full wave simulation approach is very time consuming, when feasible. Commonly, large arrays are approximated by infinite array approach or studied by single (isolated) element analysis. Being simplified approaches,...
Phased-array antenna systems are playing an increasingly significant role in passive, i.e., receive-only, radio-astronomy applications. They provide attractive features, such as a large instantaneous field-of-view, multi-beaming capability, and rapid response time. In this paper, we present an overview of current developments in phased-array antenna systems for radio astronomy, with an emphasis on...
The field-of-view of a reflector-based radio telescope can be significantly increased by using phased array feeds (PAFs). Such PAFs need to be polarimetrically calibrated to allow proper reconstruction of the polarization state of the radio waves received. In this paper, we present far field radiation patterns of the Aperture Tile-in-Focus (APERTIF) system on the Westerbork Synthesis Radio Telescope...
Present day synthesis radio telescopes have limited survey capabilities because of field of view restrictions. A novel method to form multiple beams on the sky is to employ a phased array feed (PAF). In telescopes with small f/D ratios, it is the only way to form closely packed beams on the sky. An additional advantage of this technique is that a PAF allows optimizing the secondary beam in terms of...
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