Highly Efficient Broadband Pyramidal Horn Antenna With Integrated H-Plane Power Division

Abstract

The concept and development of a highly efficient pyramidal horn is described. The radiating element comprises a rectangular radiating aperture fed by two smaller flared square waveguide sections via a bifurcated H-plane surface discontinuity. For the simultaneous feeding of the 2-port radiating element, the total antenna includes a compact H-plane power divider. Properly weighted TEn0 modes (n∈N * ) are excited at the output of the two flared waveguide sections. The bifurcation is responsible for the recombination of the incoming fields. The lowdispersive modal coupling coefficients (or transmission coefficients of the bifurcation's generalized scattering matrix) between the excitation and the aperture modes enable the broadband realization of the targeted aperture modal content. The common waveguide section is responsible for the phase alignment of the aperture modes. The design method targets a pre-optimized model which approximates the amplitude of the aperture modes TEm0 (m = 1, 3, 5, …) in the order of 1/m and minimises their relative phase difference. Finally, maximum aperture efficiency can be achieved by fine tuning and with low computational complexity. Design principles are given and illustrated by means of an example involving an antenna with aperture size of about 2.8λ0×1.4λ0 (λ0 being the free-space wavelength at the central frequency of operation). The antenna exhibits aperture efficiency levels above 95% over the entire Ku-Tx band (10.7 -12.75 GHz), as well as a compact profile (4.1λ0). The measured results of a prototype manufactured through milling verify experimentally the numerically predicted performance.

Quad-Furcated Profiled Horn: The Next Generation Highly Efficient GEO Antenna in Additive Manufacturing

“…As observed, the worst-case differences between simulated and measured values are of the order of ±0.2 dB (which translates to about ±4% in terms of aperture efficiency). We note that deviations of the order of ±0.2 dB owing to the uncertainty of the gain measurements are commensurate with what is reported in the literature [2], [23], [28]. These discrepancies are also attributed to the standard manufacturing tolerances as well as the uncertainty of the simulation tools and the effective conductivity employed to consider the excessive losses from the surface roughness produced by the printing process.…”

“…This means that in order to generate the mode TE20, some waveguides from the tapered profile of the total feed waveguide section have been displaced laterally. Moreover, in contrast to the simpler bi-furcated case [28], every adjacent feed waveguide section is symmetric with respect to both x ẑ and y ẑ planes with reference to Figs. 1(b) and 1(e), resulting in a mirror symmetric array of the four feed waveguide sections.…”

“…These in turn excite a 4-furcated waveguide surface discontinuity which is connected to a common square waveguide leading to the radiating aperture. An initial approximation of the design concept was first implemented in a single-polarized bi-furcated H-plane horn antenna [28]. After experimentally verifying the high levels of aperture efficiency, the more demanding in terms of complexity but more important in terms of practical needs Q-FPHA was further studied and developed.…”

Generalized Design Methodology of Highly Efficient Quad-Furcated Profiled Horns With Larger Apertures

“…The first one refers to the fact that the common waveguide modes TE 10 and TE 70 couple in the same way to the three excitation waveguide modes TE 10 , TE 20 , and TE 30 . The next two comments regard the impact of the third excitation mode that has been considered in contrast to the previous moderate aperture size cases [9][10][11]; the TE 30 mode (|h in 30 | • e −j∆φ in 30 ). The interaction of this mode with the common waveguide mode F h 30…”

“…The concept of utilizing more than one multimode waveguide access to feed the radiating aperture of a horn was recently developed [8,9]. Highly efficient, compact, and broadband horns were designed and manufactured in single [10] and dual polarizations [11], redefining the state-of-the-art. Both of these multi-access radiators present aperture sizes from 2.6λ 0 to 2.8λ 0 ; typical aperture sizes for Geostationary Orbit (GEO) antennas.…”