Effects of the Number of Active Receiver Channels on the Sensitivity of   a Reflector Antenna System with a Multi-Beam Wideband Phased Array Feed
  A method for modeling a reflector antenna system with a wideband phased array feed is presented and used to study the effects of the number of active antenna elements and associated receiving channels on the sensitivity of the system. Numerical results are shown for a practical system named APERTIF that is currently under developed at The Netherlands Institute for Radio Astronomy (ASTRON) 
Oleg Iupikov
astro-ph.IM