Some studies [1-3] have demonstrated that a multisources EBG resonator antenna can achieve, on its upper surface, directive and overlapped focal feeds permitting to realize passively a multispots coverage with only one reflector antenna. This paper deals with the design of a metallic Electromagnetic Band Gap antenna in Ka band dedicated to a Side Fed Offset Cassegrain Antenna for Europe multispots coverage. This reflector antenna which has a large focal length to diameter ratio limiting the defocusing effects, requires high focal feeds directivity. The well known drawback of an EBG antenna is the weak radiation bandwidth when the directivity reached is important. Moreover, the radiation patterns of classical EBG antenna fed by patches suffer from high sidelobes reducing the reflector antenna efficiency. Consequently, the works presented in this paper have consisted in the improvement of the performances of the EBG antenna thanks to a replacement of the classical source (patch…) by a horn. A 24 dB metallic EBG antenna excited by one horn has been realised at 30 GHz. The directivity varies only of 2.5 dB on the 1.5% frequency band (5 dB for the classical EBG antenna fed by patch), the side lobes measured of this antenna are lower than -30 dB. The efficiency of the SFOCA illuminated by this EBG prototype is higher than 70% on the total frequency range 29.5-30 GHz.
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