An application of Kern's 'Transmission integral' to defocusing errors in offset-fed parabolic reflector antennas

Abstract

Kern's "transmission integral" is used to calculate defocusing errors on offset-fed parabolic reflector antennas. This approach yields the scattering matrix for the parabolic reflector and is therefore applicable to any type of feed. Sample calculations of the two-dimensional (2-D) fast Fourier transform are given for a parabola with focal length to diameter ratio of 0.4.

Thermal Effects on a 4.2 m Center-Fed Cassegrain Antenna Strut in the Alphasat Ka- and Q-/V-Band Aldo Paraboni Propagation Measurements

“…Being that the wavelengths are equal to 15.2 and 7.6 mm, at 19.701 and 39.402 GHz, respectively, the values of ∆ , ranging from -3.4 mm to +3.4 mm, are definitely compatible with a defocusing effect. The obtained results are also comparable to the theoretically derived ones for different antenna geometries in [7], [8].…”

“…This contribution offers a comprehensive investigation of this anomaly to identify the causes and, to a larger extent, to provide insights on a problem that might affect other receiving equipment in the frame of propagation experiments, or that can have a non-negligible impact on the performance of gateways in near future Satcom systems operating at Q/V band. A similar effect has been theoretically studied and simulated in the literature [7]- [8] for the single reflector case and [9] for the classical center-fed Cassegrain case.…”

Three-Dimensional Equivalent Focused Feed for an Offset Paraboloidal Reflector Antenna

“…This method as well as the other methods (Ott, 1991) can also be used for error performance analysis due to the effect of defocusing. As a result, we can say that equivalent feed is a very useful method for offset paraboloidal reflector antennas with feed displacements of small and moderate sizes as well as symmetric configurations.…”