WO2006127612A2

WO2006127612A2 - Tri-band circularly-polarized elliptical feed horn

Info

Publication number: WO2006127612A2
Application number: PCT/US2006/019753
Authority: WO
Inventors: Hamid Moheb; Michael Penley
Original assignee: General Dynamics Satcom Technologies, Inc.
Priority date: 2005-05-23
Filing date: 2006-05-23
Publication date: 2006-11-30
Also published as: WO2006127612A3

Abstract

A system for and method of establishing communications between the Earth and one or more satellites are provided. The system and method include an antenna horn feature, which is compact, easy to manufacture, and reliable. The antenna horn (Figure 1) is capable of transmitting and receiving signals in multiple bands, such as, for example, Ka, K, and Ku bands.

Description

TRI-BAND CIRCULARLY-POLARIZED ELLIPTICAL FEED HORN

Field of the Invention

[0001] The present invention generally relates to corrugated feed horn assemblies capable of receiving and transmitting signals.

Description of Related Art

[0002] An important design concern for most antennas is their overall size. Smaller antennas are generally desirable for reasons of aesthetics. On the other hand, antennas preferably should have beam widths narrow enough to minimize interference from adjacent satellites, which may be as close as 2° apart. [0003] The satellite communication industry is also leaning more toward wider bandwidth to accommodate expanded services at lower cost. Broadband technology is useful for high-speed, interactive, internet protocol traffic, digital video, and multimedia applications. Consequently, the next generation of geostationary satellites is designed to combine both Ku (receive and transmit) and K/Ka bands to provide extensive bandwidth capacity and to bundle various high speed programming on the same satellite services.

Brief Description of the Drawings

[0004] The novel features that are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its structure and operation together with the additional objects and advantages thereof are best understood through the following description of exemplary embodiments of the present invention when read in conjunction with the accompanying drawings. [0005] Fig. 1 illustrates a circularly polarized tri-band elliptical feed horn with corrugation parallel to the horn axis according to an embodiment of the present invention.

[0006] Fig. 2 illustrates a circularly polarized tri-band elliptical feed horn with corrugation normal to the horn axis according to an embodiment of the present invention.

[0007] Fig. 3 depicts two cross-section views of an elliptical feed horn according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention. As used throughout this disclosure, the singular forms "a," "an," and "the" include plural reference unless the context clearly dictates otherwise. [0009] Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods, devices, and materials are now described. [0010] Certain embodiments of the present invention are designed to overcome the above-mentioned problems relating to antenna size and multi-band capacity. Solutions to the antenna size problem include using a large antenna having excess gain and narrow beam, or an elliptical reflector profile to provide narrow beamwidth, avoiding the excess gain and having a low profile as well. Technical challenges include the design complexity of combining three receive and transmit frequency bands in one feed horn and utilizing a single antenna terminal to address customer needs.

[0011] Certain embodiments of the present invention include a feed horn for use in an antenna assembly having a non-circular reflector. Such a feed horn is designed to allow the antenna assembly to support two-way (receive/transmit) communication of circularly polarized signals. The feed horn is capable of tri-band dual circularly and/or linearly polarized operation. In certain embodiments of the present invention, a feed horn with reflector assembly is configured either as circular and/or linear polarization. [0012] Embodiments of the present invention are capable of operation using a plurality of bands for transmission and reception. In certain embodiments of the present invention, three bands, namely Ku, K, and Ka, provide two receive channels (Ku, K) and two transmit (Ku, Ka) channels to one or more co-located geostationary satellites. Each satellite may be capable of transmitting and receiving signals on one or more band. Thus, certain embodiments of the present invention are capable of quad-band communication.

[0013] Fig. 1 illustrates horn geometry according to an embodiment of the present invention. More particularly, Fig. 1 illustrates a circularly polarized tri-band elliptical feed horn with corrugation parallel to the horn axis according to an embodiment of the present invention. The feed horn includes a coaxial circular waveguide section to separate Ku from K/Ka bands. The coaxial section is connected to a circular waveguide section which supports the three bands of operation. A conical waveguide section is connected to a circular waveguide section to electrically transition from the circular waveguide section to a non-circular corrugated waveguide section. [0014] The dual-depth configuration of the embodiment of Fig. 1 supports both Ku and K/Ka-band propagation. The dual-depth concept allows for operation with two distinct frequency bands, namely, Ku and K/Ka. In one embodiment of the present invention, the K/Ka-bands are combined as a first band and Ku as a second band.

[0015] Fig. 2 illustrates a circularly polarized tri-band elliptical feed horn with corrugation normal to the horn axis according to an embodiment of the present invention. In contrast to the embodiment of Fig. 1, the embodiment of Fig. 2 includes corrugation positioned normal to the horn axis. As with the embodiment of Fig. 1, the embodiment of Fig. 2 includes one set of corrugations for handling K and Ka band signals and another set of corrugations configured to handle both receive and transmit Ku band signals. The embodiments of Fig. 1 and Fig. 2 are both configured to provide proper amplitude and phase, by way of non-limiting example, over three bands. [0016] Fig. 3 depicts two cross-section views of an elliptical feed horn according to an embodiment of the present invention. The cross section views of Fig. 3 illustrate a plurality of corrugations in the corrugated waveguide section, transitioning for a circular shape adjacent to the conical waveguide section to an increasing non- circular shape at an end proximal to the reflector of the antenna assembly. The corrugations have dual individuals depths defined in the inner wall of the corrugated waveguide section. One set of corrugations is configured to handle K and Ka band signals; the other set is configured to handle both receive and transmit Ku band signals. [0017] An embodiment of the present invention may function as a broadband antenna to support both K/Ka and Ku. Preferably, the overall horn is optimized so as to obtain proper amplitude and phasing for all three bands of operation over a non- circular cross-section. This may be achieved by adjusting corrugation width and teeth to compensate the phase and amplitude for the ellipticity of the reflector. [0018] Applications of certain embodiments of the present invention include the following. Both commercial and military applications are contemplated. Applications for end user consumers are also contemplated. Data sent and received by embodiments of the present invention may include, by way of non-limiting example, data in Internet Protocol ("IP") form (such as internet data), multi-media information (such as audio and/or video), voice data (such as voice-over-IP), military information (such as logistical and surveillance information), and other types of information.

Claims

CLAIMS What is claimed is:

1. A feed horn for receiving and transmitting circularly polarized signals, the feed horn comprising: a coaxial circular waveguide section configured to separate signals in a first band and signals in a second band from signals in a third band; a conical waveguide section operatively coupled with the coaxial circular waveguide section; wherein the conical waveguide section comprises a first set of corrugations configured for handling signals of the first band and signals of the second band; wherein the conical waveguide section further comprises a second set of corrugations configured for handling signals of the third band; wherein the first set of corrugations and the second set of corrugations are substantially circular at a base of the feed horn; and wherein the first set of corrugations and the second set of corrugations transition to substantially elliptical at a distal end of the feed horn.

2. The feed horn of claim 1 wherein the first set of corrugations are parallel to an axis of the feed horn.

3. The feed horn of claim 1 wherein the first set of corrugations are perpendicular to an axis of the feed horn.

4. The feed horn of claim 1 wherein the first set of corrugations and the second set of corrugations are configured to compensate for phase differences.

5. The feed horn of claim 1 wherein the signals of the first band, the signals of the second band, and the signals of the third band are circularly polarized.

6. The feed horn of claim 1 wherein the signals of the first band, the signals of the second band, and the signals of the third band are linearly polarized.

7. The feed horn according to any of the preceding claims wherein the first band is K, the second band is Ka, and the third band is Ku.

8. The feed horn according to any of the preceding claims configured to receive signals of the first band and signals of the third band and transmit signals of the second band and signals of the third band.

9. The feed horn of any of the preceding claims wherein the third band comprises signals of frequency less than 11 GHz.

10. The feed horn of any of the preceding claims wherein at least one of the first band and the second band comprises signals of frequency between 12.75 GHz and 60 GHz.