Profiled smooth conical horn
Image of the Profiled smooth conical horn.

The performance of smooth-wall horns may be improved through a number of techniques, one of which involves profiling the flare. The ease of manufacturing at the millimeter-wave range is a huge advantage, as the fabrication of corrugated horns can become extremely costly and difficult. Other advantages include controlling the mode conversion and improving the symmetry and side lobe level of the radiation pattern.

Compared to the linear conical horn, some of the profiled horns have improved pattern symmetry and reduced sidelobe levels, while others do not. It was found that the tangential and exponential profiles provide the best alternative to the linear profile. Available profiles for this antenna include sinusoidal, tangential, exponential, hyperbolic and polynomial. Variables controlling the shape of the profiles include a profile power index (p) and a profile addition index (A), which are chosen (where applicable) as Sinusoidal (p=2, A=0.3), Tangential (p=2, A = 0.6) and Polynomial (p=4).

The introduction of the correct profile results can provide a more symmetrical beam, but at the expense of size.

E-plane pattern comparison of the 18 dBi profiled (tangential and exponential) vs. linear conical corrugated horns
H-plane pattern comparison of the 18 dBi profiled (tangential and exponential) vs. linear conical corrugated horns