A Novel Spline-Profile Diagonal Horn Suitable for Integration Into THz Split-Block Components

This paper presents a novel diagonal horn design with improved performance over a standard diagonal horn. This is achieved by applying a spline curve to the vertical cutting axis of the “V” cutting tool, while retaining the ease of direct machining into a split block. The smooth curve does not present step changes, enabling a large radius cutter to be used. The cross polarization is reduced from −10 to <−20 dB and copolar sidelobes are also reduced. Power coupling to a single linear polarization fundamental Gaussian mode is improved from 84% to approximately 97%, similar to smooth-walled spline horns and only slightly worse than a conventional corrugated horn.