Performance evaluation of satellite active antennas for a multibeam European coverage at Ku-band

A comparison is made between an antenna configuration using near-field single reflector optics (NFO) and a more conventional focusing antenna (far-field optics) with the aim of showing the impact on the hardware complexity of the departure from the far-field optics. The results show that there are no particular advantages in using focusing antenna systems for generating multibeam coverages, with regard to overall hardware complexity. The required number of feeds and spots, to cover the same service area, are more or less the same (BFN complexity), while the reflector diameter has to be oversized, in the unfocusing antenna case, to maintain a uniform amplitude over the feeding array. Because NFO is capable of concentrating the RF-power resources in the zones where the traffic is present, this antenna configuration is more flexible for use in changing traffic.<>