High-efficiency Horns Research Articles

On the development of Antenna feed array for space applications by additive manufacturing technique

Space agencies are looking for advanced technologies to build light weight and stiff payload components to bear space environment and launch loads. Additive manufacturing (AM) techniques like Direct Metal Laser Sintering (DMLS) is one of the suitable option which can be explored for space applications. This paper highlights the development process of Antenna Feed Array (AFA) using DMLS as an Additive Manufacturing (AM) technique. A high efficiency horn element is used in the array. Such horns are preferred for this development as they are the prime choice for feed elements in High Throughput satellites (HTS) that employ Multibeam Antennas. A brief description of Multibeam antennas along with the RF design process for the high efficiency horn is presented. In the development process, certain design rules of AM are adopted based on consideration to produce self-sustaining structures. AFA realized by DMLS is evaluated by functional testing, vibration testing for space qualification test levels. Test results shows its structural intactness which proves its space worthiness. Procedures are very well established for further development of space payload components.

Dual-Band Multiple Beam Antenna System Using Hybrid-Cell Reuse Scheme for Non-Uniform Satellite Communications Traffic

This paper presents an advanced dual-band antenna system suitable for broadband satellites that is capable of providing higher EIRP, higher G/T, and improved copolar isolation among frequency reuse beams. The antenna system employs a hybrid-cell frequency reuse scheme instead of conventional fixed cell reuse (4-cell or 7-cell) in order to efficiently use spectrum based on traffic demands. It is shown that the advanced antenna employing high-efficiency horns and shaped reflectors provide about 1.0 dB EIRP improvement, 2.0 dB G/T improvement, and 3.0 dB improvement in C/I when compared to conventional antennas.

Intellectual Property and Patent Abstracts

A collection of 12 patents along with abstracts and diagrams where applicable. Also listed are inventors, assignees, and dates filed. Covers some of the following technologies, theories, and schemes: a triple polarized patch antenna; an aperiodic array antenna; high-efficiency horns for an antenna system; a coaxial cable having high radiation efficiency; and a parasitic element for a helical antenna.

Comments on "Design of High Efficiency Circular Horn Feeds for Multibeam Reflector Applications

The above paper (K.K. Chan and S.K. Rao, 2008), has been read with considerable interest. We wish to point out that the design, including radiation and wide-bandwidth characteristics, of multiflared high-efficiency horns has already been published in an invention disclosure (A.K. Bhatacharyya and J. Sor, 2004) which has been in the public domain since June 8, 2006. The high-efficiency multiflared horn structure was first designed in 2003 at the company of the first author. Since then, the structure has been used as radiating elements for arrays and as reflector feeds in several communication satellite projects.

Reply to “Comments on `Design of High Efficiency Circular Horn Feeds for Multibeam Reflector Applications'”

The above paper (Chan and Rao, 2008), has been read with considerable interest. We wish to point out that the design, including radiation and wide-bandwidth characteristics, of multiflared high-efficiency horns has already been published in an invention disclosure (Bhattacharyya and Sor, 2004) which has been in the public domain since June 8, 2006. The high-efficiency multiflared horn structure was first designed in 2003 at the company of the first author. Since then, the structure has been used as radiating elements for arrays and as reflector feeds in several communication satellite projects.

Stepped-Reflector Antenna for Dual-Band Multiple Beam Satellite Communications Payloads

A novel stepped-reflector antenna (SRA) suitable for dual-band multiple beam satellite payloads is introduced in this paper. The SRA system produces "flat-top" radiation patterns for receive beams and highly efficient Gaussian patterns for transmit beams over a geographic coverage region as seen by the geo-synchronous satellite. It combines the reflector improvements through the use of SRA with the feed horn advancements through the use of dual-band "high-efficiency horns" in order to realize an efficient multiple beam antenna (MBA) system supporting both downlink transmit and uplink receive signals of communication satellites. It is shown that the SRA provides a congruent set of spot beams on ground for both transmit and receive frequencies with the benefits of significantly improved edge-of-coverage gain, improved co-polar isolation among beams that re-use the same frequency channels, receive beam patterns that are less sensitive to satellite pointing error, and reduced number of reflector antennas when compared to conventional MBAs

A Novel Horn Radiator With High Aperture Efficiency and Low Cross-Polarization and Applications in Arrays and Multibeam Reflector Antennas

A step horn structure is presented that yields about 90% aperture efficiency with low cross-polar radiation. It is found that for obtaining high aperture efficiency, the horn aperture should consist of only the TE/sub z/ type of modes in appropriate amplitudes and phases. The desired TE/sub z/ modes are produced using multiple steps in the horn walls. The distances between the steps are critical to suppress the undesired TM/sub z/ modes. Radiation characteristics of high efficiency circular and square horns are presented and potential applications of such high efficiency horns are discussed.

Loudspeakers

A loudspeaker is an electroacoustic transducer intended to radiate acoustic power into the air, the acoustical waveform being essentially equivalent to that of the electrical input. Electrodynamic, electromagnetic and electrostatic driving systems have been used for loudspeakers operating in air. However, during the past two decades the electrodynamic has overwhelmingly predominated in all applications for loudspeakers operating in air. The almost universal use of the direct-radiator dynamic loudspeaker in radio receivers, phonographs, magnetic-tape reproducers, television receivers, announce and intercommunicating systems is due to the simplicity of construction, small space requirements and the relatively uniform response-frequency characteristics. For small-scale applications the low efficiency of the direct-radiator loudspeaker is not a handicap. However, for large-scale high-power sound applications, the high-efficiency horn loudspeaker is particularly suitable because the amplifier requirements are reduced by an order of magnitude. For the future, the promising developments in loudspeakers appear to be in the field of motion control.