An Electrically Steerable Array of 968 Dipoles for the Ooty Radio Telescope

Abstract

An electrically steerable array of 968 dipoles for illuminating the parabolic antenna of the Ooty radio telescope at 327 MHz is described. The array has been divided into 22 modules of 44 dipoles each. Dipoles in each module are fed in series through directional couplers and phase shifters. A simple design of trombone type phase shifters with non-contacting choke joints has been developed that gives a loss of less than 1.2 dB in each module at 327 MHz. The antenna beam can be steered between ±36° in declination.