High Efficiency Phased Array receivers for Radio Astronomy,
Remote Sensing and Satellite Communciations
by Karl Warnick (Brigham Young
University, USA)
Abstract. Aperture phased arrays
and phased array feeds (PAFs) are a promising technology for sensing and
communications applications requiring electronic beamsteering and large signal
collecting area. The phased arrays that have been in use for radar and
communications for many decades typically have relatively low antenna
efficiencies, as the signal environment for terrestrial applications has a
high ambient temperature and intensive optimization of receiver sensitivity
yields only modest performance gains. For radio astronomy, remote sensing,
and satellite communications, the situation is different. High radiation
efficiency, low noise electronics, compensation for mutual coupling effects,
and careful design optimization are needed to meet stringent performance
requirements, and these applications have stimulated something of a renaissance
in phased array antenna research. This presentation will survey results on
antenna modeling, microwave network theory, antenna design, and experimental
characterization for high sensitivity array receiver applications. Systems
across the spectrum of applications will be considered, from cryogenic phased
array feeds for astronomical observations to planar array feeds for smart
satellite terminals that offer adaptive tracking at a low cost. Antenna
terms in the latest revision of the IEEE standard for antenna terms and array
characterization methods will also be discussed. Finally, the presentation
will review open challenges such as determining the quality of active impedance
matching in an array feed system, array element radiation loss modeling and
measurement, and reducing instabilities in formed images with phased array
feeds.
