Multi-Band 7.1/8.5/20/30-GHz Horn Antenna with Spline-Taper and Coaxial-Groove Walls

This paper proposes a new horn antenna with a coaxial-groove structure using a spline-taper with small protrusion four bands of 7.1/8.5/20/30 GHz. This horn has a good VSWR and low cross-polarization characteristics at the designed frequencies, yet for 20/30 GHz the electric field is controlled to pass near the center without affecting the discontinuities near the aperture plane.