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

Abstract

A novel compact and highly efficient dual-polarized horn-like antenna is presented. It exploits a radiating aperture that is fed by four smaller waveguides via a quad-furcated junction. The antenna also comprises the full feed network for the feed waveguides including an integrated 4-way orthomode power divider. Design principles are described in detail and illustrated by means of an example involving an antenna with aperture size of 2.6λ0×2.6λ0 (λ0 the wavelength at the central frequency of operation) intended primarily for Geostationary Orbit (GEO) satellites. The antenna feed was designed to comply with the Additive Manufacturing rules and exhibits aperture efficiency levels close to the theoretical maximum ones over the entire transmit Ku band (10.7 -12.75 GHz), while at the same time its profile is highly compact (6.4λ0). The measured results of a prototype 3D-printed in Selective Laser Melting (SLM) verified experimentally the calculated high aperture efficiency (over 90%). The total antenna feed attains return loss > 19 dB and maximum cross-polarization isolation (XPI) > 24 dB over a bandwidth of 18%. In light of the favorable electrical performances and compact size, the proposed solution constitutes an appealing alternative to profiled (or spline) horns for satellite antenna systems used either as reflector feeds or direct radiating arrays.

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…”

“…Experimental verification of structurally similar high aperture efficiency Bi-and Quad-FPH elements can be found in [10] and [11], respectively. These antennas have electrically moderate square aperture sizes and were developed before the generalization of the methodology presented in this paper.…”

“…These antennas have electrically moderate square aperture sizes and were developed before the generalization of the methodology presented in this paper. It is last mentioned that although the presented design case has been characterized numerically without including materials and hence loss analysis, from former knowledge [11], ohmic losses of about 0.1 dB are expected for non-treated 3D-metal printed antenna feeds which employ the 4-port radiating element with the feeder [19].…”

“…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.…”

Monolithically Integrated Coaxial Resonator-Based Filtennas Using SLA Three-Dimensional Printing

“…In the recent years, digital additive manufacturing (DAM) has become a low-cost alternative for the prototyping of antenna elements. Metal-based AM process such as direct metal laser sintering (DMLS) [7] or selective laser melting (SLM) [8], [9] offers high mechanical robustness, but with relatively higher cost and low surface roughness. Ceramic based-or plastic/resin based-AM process [10] [11]- [17], PolyJet [18], and stereolithography apparatus (SLA) [19]- [21] exhibit significantly lower cost and weight.…”