Spline-profile smooth-walled horn as a feed of the multi-beam millimetre focal plane array

In this paper simulated and measured characteristics of an optimized smooth-walled spline-profile horn for two-dimensional multibeam focal plane array at RATAN-600 radio telescope are presented. The measured -10 dB beamwidth is less than 45° in the H-and E-planes. The measured side-lobe levels of the radiation pattern are less than -18 dB in the both principal planes. The measured input reflection coefficient is better than -21dB in the frequency range 30 GHz - 38 GHz. The experimental results are in good agreement with simulated ones in the operational frequency band 34 GHz - 38 GHz.