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We describe the design and construction of a dual-polarized phased-array feed (PAF) with the purpose of demonstrating this technology as a means of expanding the instantaneous field-of-view of radio telescopes. The PAF beamformer is calibrated with observations of an unpolarized astronomical radio source, the covariance matrix of all receiver channels is calculated, and the two dominant eigenvectors...
The present day radio telescopes with single-beam feeds can achieve the dynamic range up to 106:1 in the beam on-axis direction. However, the off-axis dynamic range is severely limited by uncertainties and temporal instability in the beam patterns. A number of calibration techniques for dealing with these effects have been proposed and used in practice. For nove lphased-array based telescopes, the...
A novel method to form multiple beams on the sky with a reflector antenna is to employ a dense phased array feed (PAF). This technology is currently being developed to greatly increase the survey speed of existing and future radio telescopes. For high quality radio astronomical images the beam patterns of the telescope must be stable over the duration of the observation, which is typically 12 hours...
A low-cost ultrawideband (UWB), 1.926-4.069 GHz, phased array radar system is developed that requires only one exciter and digital receiver that is time-division-multiplexed (TDM) across 8 receive elements and 13 transmit elements, synthesizing a fully populated 2.24 m long (λ/2 element-to-element spacing) linear phased array. A 2.24 m linear phased array with a 3 GHz center frequency would require...
This paper is a summary of recent research progress towards scientifically useful low noise, high sensitivity phased array feeds for radio telescopes. Developments include techniques for designing phased array antennas to realize an active impedance matching condition that minimizes receiver noise over the array field of view, array beamforming algorithms that allow a controlled tradeoff between side-lobe...
Phased array feeds can greatly increase the field of view of interferometric radio telescope arrays. High dynamic range imaging with these arrays requires compensation for drifts in the many receiver-chain gains. A calibration system using surface radiators is proposed for the Australian Square Kilometre Array Path Finder. Design considerations and a proposed system are discussed.
A feed for a compact antenna test range operating in P-band in single polarization has been manufactured and tested in the SATIMO SG-64 multiprobe spherical near field test range in Paris. The feed consist of an array of 4 high gain log-periodic elements. This paper briefly describes the consideration on antenna design and manufacturing and report on the final testing including considerations on the...
A single polarized P-band feed, consisting of an array of 4 high gain log-periodic elements has been designed, manufactured and tested for use as illuminator in a compact antenna test range. This paper briefly describes the antenna design trade-off activity, selection of the candidate antenna technology, manufacturing and final testing including considerations on the associated measurement uncertainty...
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