HORN ANTENNA ELEMENT

Abstract

A horn antenna element includes a septum polarizer configured to transform a linear polarized input signal into a circular polarized output signal at a common port, and a horn radiator. The horn radiator includes an input geometry formed as a quad-ridge waveguide to receive the circular polarized output signal at the common port and an aperture grid to radiate a grid-based circular polarized output signal. The septum polarizer is embedded in the quad-ridge waveguide at the common port.

Claims

1. A horn antenna element comprising: a septum polarizer configured to transform a linear polarized input signal into a circular polarized output signal at a common port; and a horn radiator comprising: an input geometry formed as a quad-ridge waveguide to receive the circular polarized output signal at the common port; and an aperture grid to radiate a grid-based circular polarized output signal, wherein the septum polarizer is embedded in the quad-ridge waveguide at the common port.

2. The horn antenna element of claim 1, wherein the quad-ridge waveguide of the input geometry comprises four symmetrically formed ridges of equal size.

3. The horn antenna element of claim 2, wherein the aperture grid is formed as an array of quad-ridge waveguides, wherein the array of quad-ridge waveguides is a 2×2 array of quad-ridge waveguides.

4. The horn antenna element of claim 3, wherein the quad-ridge waveguides of the aperture grid are symmetrically formed, each of the quad-ridge waveguides having a same cross section.

5. The horn antenna element of claim 3, wherein each of the quad-ridge waveguides of the aperture grid comprises four ridges.

6. The horn antenna element of claim 5, wherein the four symmetrically formed ridges of the quad-ridge waveguide of the input geometry and the four ridges of the array of quad-ridge waveguides of the aperture grid are formed in a non-overlapping manner.

7. The horn antenna element of claim 1, wherein the septum polarizer is configured to split an input TE1,0 mode of the linear polarized input signal into a mode combination of TE1,0 and TE0,1 with +/−90 degree phase difference in between, thereby creating an either left-handed circular polarization, LHCP, signal or right-handed circular polarization, RHCP, signal to be radiated by the horn radiator.

8. The horn antenna element of claim 1, further comprising two single linear polarized ports configured to receive, transmit or a combination thereof a respective linear polarized component of the linear polarized input signal.

9. The horn antenna element of claim 8, wherein the two single linear polarized ports are configured to simultaneously receive and transmit in a K-band frequency range and a Ka-band frequency range.

10. The horn antenna element of claim 9, wherein: a reflection coefficient of the two single linear polarized ports is below a predetermined threshold and is free of resonances in both the K-band frequency range and the Ka-band frequency range; and the predetermined threshold is below −15 dB.

11. The horn antenna element of claim 9, wherein an axial ratio of the grid-based circular polarized output signal is below 1 dB in both the K-band frequency range and the Ka-band frequency range.

12. The horn antenna element of claim 8, wherein: the septum polarizer comprises continuous ridged waveguide geometries from the two single linear polarized ports to the quad-ridge waveguide of the horn radiator; and the septum polarizer is staircase-shaped to transform the linear polarized input signal into the circular polarized output signal.

13. The horn antenna element of claim 1, wherein a cross section of the quad-ridge waveguide of the horn radiator corresponds to a cross section of the aperture grid of the horn radiator.

14. The horn antenna element of claim 1, wherein a geometry of the horn radiator is oversized with respect to a wavelength at a specified maximum operation frequency and is larger than one or multiple wavelengths at the specified maximum operation frequency.

15. An airborne satellite communication system, the airborne satellite communication system comprising: the horn antenna element of claim 1; and a multi-axis positioner configured to permanently align the horn antenna element to a given target satellite.

Description

DRAWINGS

[0070] In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

[0071] FIG. 1 shows a schematic diagram illustrating a horn antenna element, according to the present application;

[0072] FIG. 2 shows a schematic diagram illustrating an airborne satellite communication system, according to the present application;

[0073] FIG. 3 shows a front view of an example horn antenna element, according to the present application;

[0074] FIG. 4 shows a perspective view of an example horn antenna element, according to the present application;

[0075] FIG. 5 shows a 3-dimensional representation of an example horn antenna element according to the present application;

[0076] FIG. 6 shows a backside view of an example horn antenna element, according to the present application;

[0077] FIG. 7 shows a cut-plane view into an example horn antenna element, according to the present application;

[0078] FIG. 8 shows a cut-plane side view into an example horn antenna element, according to the present application;

[0079] FIG. 9 shows a cut-plane perspective view into an example horn antenna element, according to the present application;

[0080] FIG. 10 shows a cut-plane front view into an example horn antenna element 100, according to the present application;

[0081] FIG. 11 shows a performance diagram illustrating S-parameters of an example horn antenna element, according to the present application; and

[0082] FIG. 12 shows a performance diagram illustrating axial ratio of an example horn antenna element, according to the present application.

[0083] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

[0084] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0085] FIG. 1 shows a schematic diagram illustrating a horn antenna element 100 according to the present application.

[0086] The horn antenna element 100 comprises a septum polarizer 110 and a horn radiator 120. The septum polarizer 110 is configured to transform a linear polarized input signal 102 into a circular polarized output signal 104 at a common port 112. The horn radiator 120 comprises an input geometry formed as a quad-ridge waveguide 121 to receive the circular polarized output signal 104 at the common port 112. The horn radiator 120 further comprises an aperture grid 124 to radiate a grid-based circular polarized output signal 106. The grid-based circular polarized output signal 106 corresponds to the circular polarized output signal 104 after passing the aperture grid 124. The septum polarizer 110 is embedded in the quad-ridge waveguide 121 at the common port 112.

[0087] Both, septum polarizer 110 and horn radiator 120 may be embedded in a housing. The embedding of the septum polarizer 110 in the quad-ridge waveguide 121 may provide for a fixed arrangement of both parts in the horn antenna element 100 such that no rotation or movement of the septum polarizer 110 with respect to the horn radiator 120 is possible. The horn antenna element 100 may be formed of a single material. It is also possible to separately produce septum polarizer 110 and horn radiator 120 and connect both parts, e.g., by fusing, welding, bonding, and/or sticking, among others.

[0088] The linear polarized input signal 102 may be fed to an input port 111 of the horn antenna element by a feeding network (not shown in FIG. 1).

[0089] The quadridge waveguide 121 of the input geometry may comprise four symmetrically formed ridges 311a, 311b, 311c, 311d of equal size, e.g., as shown in FIG. 3.

[0090] The aperture grid 124 may be formed as an array of quad-ridge waveguides 124a, 124b, 124c, 124d, e.g., as shown in FIG. 3, in one form as a 2×2 array of quad-ridge waveguides 124a, 124b, 124c, 124d as shown in FIG. 3.

[0091] The quad-ridge waveguides 124a, 124b, 124c, 124d of the aperture grid 124 may be symmetrically formed, such that each of the quad-ridge waveguides 124a, 124b, 124c, 124d has a same cross section, e.g., as shown in FIG. 3.

[0092] Each of the quad-ridge waveguides 124a, 124b, 124c, 124d of the aperture grid 124 may comprise four ridges 301a, 301b, 301c, 301d, e.g., as shown in FIG. 3.

[0093] The ridges 311a, 311b, 311c, 311d of the quad-ridge waveguide 121 of the input geometry and the ridges 301a, 301b, 301c, 301d of the array of quad-ridge waveguides 124a, 124b, 124c, 124d of the aperture grid 124 may be formed in a non-overlapping manner, e.g., as shown in FIG. 3.

[0094] The septum polarizer 110 may be configured to split an input TE1,0 mode of the linear polarized input signal 102 into a mode combination of TE1,0 (702) and TE0,1 (701) with +/−90 degree phase difference in between, thereby creating an either left-handed circular polarization, LHCP, signal 703 or right-handed circular polarization, RHCP, signal 704 to be radiated by the horn radiator 120, e.g. as shown in FIG. 7.

[0095] The horn antenna element 100 may comprise two single linear polarized ports 501, 502 as shown in FIG. 5, which are configured to receive and/or transmit a respective linear polarized component of the linear polarized input signal 102. The two single linear polarized ports 501, 502 may be received and/or transmitted at the input port 111 of the horn antenna element 100.

[0096] It understands that the horn antenna element 100 is configured to transmit and receive signals simultaneously. E.g., a K-band signal may be received while simultaneously transmitting a Ka-band signal on each port.

[0097] The two single linear polarized ports 501, 502 may be configured to simultaneously receive and transmit in a K-band frequency range 1110 and a Ka-band frequency range 1120, e.g., as shown in FIGS. 11 and 12.

[0098] In one form of configuration of the horn antenna element, a reflection coefficient 1101 of the two single linear polarized ports 501, 502 may be below a predetermined threshold, in one form below −15 dB, and may be free of resonances in both K-band 1110 and Ka-band 1120, e.g., as shown in FIG. 11.

[0099] In one form of configuration of the horn antenna element, an axial ratio 1201 of the grid-based circular polarized output signal 106 may be below 1 dB in both K-band 1110 and Ka-band 1120, e.g., as shown in FIG. 12.

[0100] The septum polarizer 110 may comprise continuous ridged waveguide geometries 511, 512, 513, 514, 611, 612 from the two single linear polarized ports 501, 502 to the quad-ridge waveguide 121 of the horn radiator 120, e.g., as shown in FIGS. 5 and 6.

[0101] The septum polarizer 110 may be staircase-shaped 801, 802, 803, 804, e.g., as shown in FIG. 8, to transform the linear polarized input signal 102 into the circular polarized output signal 104.

[0102] A cross section of the quad-ridge waveguide 121 of the horn radiator 120 may corresponds to a cross section of the aperture grid 124 of the horn radiator 120, e.g., as shown in FIG. 3.

[0103] A geometry of the horn radiator 120 may be oversized with respect to a wavelength at a specified maximum operation frequency, in one form larger than one or multiple wavelengths at the specified maximum operation frequency. Such specified maximum operation frequency may be the end of Ka-band, in one form, or higher.

[0104] FIG. 2 shows a schematic diagram illustrating an airborne satellite communication system 200 according to the present disclosure.

[0105] The airborne satellite communication system 200 comprises a horn antenna element 100 as shown in FIG. 1 or FIGS. 3 to 10. The airborne satellite communication system 200 further comprises a multi-axis positioner 203 configured to permanently align 204 the horn antenna element 100 to a given target satellite 201. A processor or controller may be used to align the horn antenna to the satellite 201. The position of the satellite may be detected by receiving a signal from the satellite. The processor may align the multi-axis positioner 203 based on the determined satellite position.

[0106] The multi-axis positioner 203 and the horn antenna element 100 may be mounted at an airplane 202, in one form at a rear wing of the airplane 202.

[0107] FIG. 3 shows a front view 300 of one form of a horn antenna element 100 according to the present application.

[0108] The quad-ridge waveguides 124a, 124b, 124c, 124d are inside vacuum. The view onto the grid 124 (shown in FIG. 1) shows the division of the single horn into a virtual 2×2 array. Volume inside the horn is at first split in 4 equal sections, preforming virtual 2×2 array and finally it is covered by the grid that completes the 2×2 array. All parts involve quad-ridge waveguide geometric features 301a, 301b, 301c, 301d, 311a, 311b, 311c, 311d.

[0109] The quad-ridge waveguide 121 of the input geometry is illustrated by the structure 310 which comprises the four symmetrically formed ridges 311a, 311b, 311c, 311d of equal size. The upper ridge 311a and the lower ridge 311c are parallel to the left and right sides of the waveguide 121. The left-side ridge 311d and the right-side ridge 311b are parallel to the upper and lower sides of the waveguide 121.

[0110] The aperture grid 124 is formed as an array of quad-ridge waveguides 124a, 124b, 124c, 124d. In this form, a 2×2 array of quad-ridge waveguides 124a, 124b, 124c, 124d is shown. However, in another form, the array can be a 3×3 array or an 4×4 array or a higher dimension array. In another form, even arrays of non-squared size can be realized, such as a 2×3 array, a 2×4 array, a 3×4 array, etc.

[0111] The quad-ridge waveguides 124a, 124b, 124c, 124d of the aperture grid 124 are symmetrically formed, such that each of the quad-ridge waveguides 124a, 124b, 124c, 124d has a same cross section. The aperture grid 124 may have a squared cross section (e.g., with rounded edges) having a size of A, in one form. Then, the cross sections of the quad-ridge waveguides 124a, 124b, 124c, 124d may each be squares (also with rounded edges) of size A/4 in this implementation.

[0112] However, in another form, even different cross sections for the quad-ridge waveguides 124a, 124b, 124c, 124d can be implemented.

[0113] Each of the quad-ridge waveguides 124a, 124b, 124c, 124d of the aperture grid 124 comprises four ridges 301a, 301b, 301c, 301d.

[0114] The ridges 311a, 311b, 311c, 311d of the quad-ridge waveguide 121 of the input geometry and the ridges 301a, 301b, 301c, 301d of the array of quad-ridge waveguides 124a, 124b, 124c, 124d of the aperture grid 124 are formed in a non-overlapping manner. (i.e., both groups of ridges do not overlap as can be seen from FIG. 3).

[0115] However, in another form, an overlapping design can be implemented. Then, ridge 311a can overlap with ridge 301b and with the corresponding ridge of the quad-ridge waveguide 124b. Similarly, ridge 311b can overlap with the corresponding ridges of quad-ridge waveguides 124b and 124c; ridge 311c can overlap with the corresponding ridges of quad-ridge waveguides 124c and 124d; and ridge 311d can overlap with the corresponding ridges of quad-ridge waveguides 124d and 124a.

[0116] FIG. 4 shows a perspective view 400 of one form of a horn antenna element 100 according to the present application. The grid 124 (as shown in FIG. 1) in front of horn is visible to divide horn aperture into a virtual 2×2 array. The grid shows quad-ridged waveguide like geometry to enable dual-band (very wideband) operation.

[0117] FIG. 5 shows a 3-dimensional representation 500 of one form of a horn antenna element 100 according to the present application. Shown is the vacuum section of the horn antenna element 100, i.e., inside vacuum of both septum polarizer 110 embedded in a quad-ridged waveguide 121 and the horn radiator 120. Continuous ridged waveguide geometries 511, 512, 513, 514 are implemented from the single linear polarized ports 501, 502 to the horn aperture.

[0118] FIG. 6 shows a backside view 600 of one form of a horn antenna element 100 according to the present application. Shown is the vacuum section of the horn antenna element 100, i.e., inside vacuum of both septum polarizer 110 embedded in a quad-ridged waveguide 121 and the horn radiator 120. The backside view is looking onto both orthogonally polarized ports 501, 502 of the septum polarizer 110. Ridged waveguide geometry 611, 612 are implemented at the input ports 501, 502. Transforming steps towards the septum polarizer 110 are visible in FIG. 6. The ridged geometry 611, 612 was chosen to reduce size (but keep cut off frequency as low as possible) of waveguide's cross-section, to be able to build a feeding network around it.

[0119] FIG. 7 shows a cut-plane view 700 into one form of a horn antenna element 100 according to the present application.

[0120] The septum polarizer 110 with its characteristic staircase shape is visible to transform linear polarized input signal 102 received at input ports 501, 502 into a circular polarized output signal 104 at the common port 112.

[0121] An input TE1,0 mode is split into a mode combination of TE1,0 (702) and TE0,1 (701) with +/−90° phase difference in between, thereby creating an either LHCP (704) or RHCP (703) signal to be radiated.

[0122] FIG. 8 shows a cut-plane side view 800 into one form of a horn antenna element 100 according to the present application. The polarizer “stair” 801, 802, 803, 804 is visible. The “staired” geometry allows for an easier manufacturing of the part.

[0123] FIG. 9 shows a cut-plane perspective view 900 into one form of a horn antenna element 100 according to the present application. The polarizer “stair” 801, 802, 803, 804 is visible.

[0124] FIG. 10 shows a cut-plane front view 1000 into one form of a horn antenna element 100 according to the present application. The polarizer 110 is completely embedded into a quad-ridge waveguide geometry.

[0125] FIG. 11 shows a performance diagram illustrating S-parameters 1100 of one form of a horn antenna element 100 according to the present application. The graph above shows an example of S-parameter performance data.

[0126] S11 is the reflection coefficient 1101 of the linear polarized ports 501, 502 which is below 15 dB and free of any resonances in both K/Ka frequency bands. K frequency band is denoted as 1110 and Ka frequency band is denoted as 1120.

[0127] S21 is the isolation 1102 between both linear polarized ports 501, 502 which shows the characteristic dual-band behavior. Isolation 1102 is high enough for K-band Rx frequency range (17.7 GHz-20.2 GHz) and Ka-band Tx frequency range (27.5 GHz-30 GHz).

[0128] FIG. 12 shows a performance diagram illustrating axial ratio 1200 of one form of a horn antenna element 100 according to the present application.

[0129] The graph shows expected very good axial ratio 1201 performance with values <1 dB in both Rx and Tx frequency range, i.e., K-band Rx frequency range (17.7 GHz-20.2 GHz) and Ka-band Tx frequency range (27.5 GHz-30 GHz).

[0130] The horn antenna element 100 as presented in the present application can be used as but is not restricted to a Ka Band antenna as part of an airborne satellite communication system. The horn antenna element 100 can be implemented together with another antenna design for Ku-Band such that user have the advantage to choose between Ku- or Ka-band products using one and the same platform. The antenna can be used, in one form, as a tailmount antenna, or as another type of antenna. The horn antenna element 100 can also be used as an antenna in other frequency ranges not described in the present application.

[0131] While one form of the present application may have been disclosed with respect to only one of several implementations, such feature or aspect may be combined with one or more other features or aspects of the other implementations as may be desired and advantageous for any given or particular application. Furthermore, to the extent that the terms “include”, “have”, “with”, or other variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term “comprise”. Also, the terms “exemplary”, “for example” and “e.g.” are merely meant as an example, rather than the best or optimal. The terms “coupled” and “connected”, along with derivatives may have been used. It should be understood that these terms may have been used to indicate that two elements cooperate or interact with each other regardless of whether they are in direct physical or electrical contact, or they are not in direct contact with each other.

[0132] Although specific aspects have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific aspects shown and described without departing from the scope of the present application. This application is intended to cover any adaptations or variations of the specific aspects discussed herein.

[0133] Although the elements in the following claims are recited in a particular sequence with corresponding labeling, unless the claim recitations otherwise imply a particular sequence for implementing some or all of those elements, those elements are not necessarily intended to be limited to being implemented in that particular sequence.

[0134] Many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the above teachings. Of course, those skilled in the art readily recognize that there are numerous applications of the present disclosure beyond those described herein. While the present disclosure has been described with reference to one or more particular forms and/or variations, those skilled in the art recognize that many changes may be made thereto without departing from the scope of the present disclosure. It is therefore to be understood that within the scope of the appended claims and their equivalents, the present disclosure may be practiced otherwise than as specifically described herein.

[0135] Unless otherwise expressly indicated herein, all numerical values indicating mechanical/thermal properties, compositional percentages, dimensions and/or tolerances, or other characteristics are to be understood as modified by the word “about” or “approximately” in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice, material, manufacturing, and assembly tolerances, and testing capability.

[0136] As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”

[0137] The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.