Smart radome improves reflector antenna directivity

To ensure protection from dust, wind, rain and snow, reflector antennas are covered with spherical dielectric radomes. However, normally it is considered that the presence of the radome in the near zone of the reflector is a negative factor in the electromagnetic sense. The antenna performance suffers: the main beam is typically distorted, and the sidelobe level increases and the directivity is lost. In part, this is due to the fact that such antenna systems are not designed in a self-consistent manner, taking fully into account all the interactions between the elements. We demonstrate that an accurate numerical optimization procedure can bring a different vision of this situation. By a clever manipulation of the radome thickness, its radius, the reflector location inside the radome, and the position of the feed, one can improve the antenna performance with respect to the free-space reflector. To reach this goal, the optimization code must be based on solving a rigorous integral equation by means of the regularization technique, guaranteeing the desired accuracy.