The invention relates to a device for exciting a centrally focused reflector antenna, comprising a waveguide (1), a dielectric field transformer (2) arranged on said waveguide (1) and a mounting platform (3) for a series of modules (8) which is embodied on one end of the waveguide (1). The waveguide (1) is provided with a means for receiving the dielectric field transformer (2) which partially protrudes into the waveguide (1). In a preferred embodiment, a dielectric support (9) is provided in the vicinity of the dielectric field transformer (2). The middle of said support has a circular bore (12) whose diameter corresponds to the diameter of the dielectric field transformer (2). One advantage of the invention is that the centrally focused reflector antennae can be excited in the focal point thereof in a field-optimum broadband manner. No mechanically displaced components are required as a result of the dielectric field transformer. The inventive device can be produced in a cost-effective manner with high mechanical precision and little effort. It is characterized by high tolerance with respect to various environmental conditions such as temperature, humidity of the air and aggressive media.