S. V. Ermolaev - Leading Engineer in Radio Communications, FSUE Radio Research and Development Institute (NIIR). E-mail: ermolaev@niir.ru

The references [1-3] give a method to calculate dual-reflector antennas using complex coordinates. Their equations allow calculating profiles of a reflector and a convergent reflector of a dual-reflector antenna with an offset feeder and co-phased field distribution across its aperture. The paper proposes a method to calculate the reflector surface of a dual-reflector antenna using the specified surface of a convergent reflector and vice versa, ensuring co-phased field distribution across aperture of the dual-reflector antenna. The paper gives the necessary equations which allow the calculation. The equations allow, for example, calculating the geometry of both spherical [4] and toroidal dual-reflector antennas, as well as calculating the surface of a convergent reflector to correct phase errors due to distortion of reflector surface (for example, distortion due to gravitation). The equations based on the studies [5] allow calculating caustics of beams reflected from a main reflector or a convergent reflector. Also there are the relations ensuring that a surface of a reflector or a convergent reflector is in the single-beam area for beams reflected from a convergent reflector or a main reflector, accordingly.