Analysis of the strut and feed blockage effects in radio telescopes with compact UWB feeds

The international radio astronomy community is currently pursuing the development of a giant radio telescope known as the Square Kilometre Array (SKA). The SKA reference design consists of several wideband antenna technologies, including reflector antennas fed with novel multi-beam Phased Array Feeds (PAF) and/or wide band Single Pixel Feeds (SPFs) that can operate at frequencies from 1 to 10 GHz. The baseline of this design represents an array of several hundred to a few thousand reflector antennas of 15-m diameter and that will realize sensitivity of 10,000 m²/K. During the past years, several different reflector and feed concepts have been proposed and examined, but only a small number of these design options (that have a sufficient level of maturity) will be built and tested in a set-up that is closely resembling the final SKA system. These tests are aimed to evaluate the overall system performance as well as construction and operational costs. The final choices for the dish and feed evaluation tests might include: (i) off-set Gregorian and axi-symmetric reflector antennas and; (ii) an optimized octave corrugated horn and the single-pixel wideband feeds such as quad-ridged horn and Eleven antenna.