Prototype of 32-element horn antenna array for imaging reflector antenna of 21-GHz band broadcasting satellite

A 21-GHz band satellite broadcasting system is being studied as a means of delivering 8K (Super Hi-Vision), 3DTV, and other advanced forms of broadcasting. We assumed the use of two 300-MHz class wideband channels in the 21.4 to 22.0-GHz band and devised an array-fed imaging reflector antenna (array-fed IRA) to supply enough power for a transponder with such a wide band. The array-fed IRA is an effective means of exploiting limited resources because of its ability to control radiation patterns; the 21-GHz band suffers from severe fading due to rain. To confirm the feasibility of the array-fed IRA system, we designed an engineering model of an array-fed IRA for a 21-GHz band broadcasting satellite. The engineering model has a feed array that consists of 32 horn antennas. To improve the accuracy of the antenna´s arrangement, we combined the 32 horn antennas into one unit. To evaluate the characteristics of this unit type feed array, we fabricated and tested a 32-element horn antenna array.