阅读说明：本技术 三频带馈送组件系统和方法 (Three-band feed assembly system and method ) 是由 C·D·让德龙 Y-C·常 P·芬恩 A·布赖洛夫斯基 于 2018-02-14 设计创作，主要内容包括：本文提供了一种在不同频带(例如,低、中和高频带)下工作的馈送组件。馈送组件包括低、中和高频带共用的馈电喇叭、用于发射在低带频带中的信号的同轴偏振器、用于发射在低带频带中的信号并支持中和高频带的同轴正交模态换能器(OMT)以及设置在馈送组件的中心导体中的多杆,该多杆对中频带和高频带共用。馈送组件包括具有不同的部分的三频带馈送组件,以支持低频带中的信号以及中频带和高频带中的信号。(A feed assembly is provided herein that operates at different frequency bands (e.g., low, mid, and high frequency bands). The feed assembly includes a feed horn common to the low, mid, and high frequency bands, a coaxial polarizer for transmitting signals in the low band, a coaxial orthomode transducer (OMT) for transmitting signals in the low band and supporting the mid and high frequency bands, and a plurality of rods disposed in a center conductor of the feed assembly, the plurality of rods being common to the mid and high frequency bands. The feed assembly includes a tri-band feed assembly having different portions to support signals in a low frequency band and signals in a mid-band and a high frequency band.)

1. A feed assembly for a reflector antenna, comprising:

a feed horn common to a low frequency band, a middle frequency band, and a high frequency band;

a coaxial polarizer that converts a signal between circular polarization and linear polarization in a low band frequency band and supports a middle band and a high band;

a coaxial Orthogonal Mode Transducer (OMT) that separates two orthogonal signals and transitions from a coaxial waveguide to a rectangular waveguide in a low-band frequency band, and supports a middle-band and a high-band; and

a plurality of rods disposed in a center conductor of the feeding assembly, wherein the plurality of rods are common to a middle frequency band and a high frequency band and support a low frequency band.

2. The feed assembly of claim 1, wherein the length of the coaxial polarizer corresponds to half the wavelength of the operating frequency in the low frequency band.

3. The feed assembly of claim 2, wherein the length of the coaxial polarizer corresponds to the properties of the material forming the coaxial polarizer and the shape of the coaxial polarizer.

4. The feed assembly of claim 1, wherein the coaxial polarizer further comprises a portion having a notched rectangular shape.

5. The feed assembly of claim 1, wherein the coaxial OMT further comprises at least two ports disposed at a predetermined distance, and wherein the predetermined distance corresponds to a return loss threshold and an isolation threshold of the reflector antenna.

6. The feed assembly of claim 1, further comprising a matching section coupled to the feed horn, the matching section being common to the low, mid, and high frequency bands.

7. The feed assembly of claim 1, further comprising a polarizer disposed in the center conductor of the feed assembly, the polarizer being common to the mid-band and the high-band.

8. The feed assembly of claim 1, further comprising a diplexer configured to separate two ports for mid-band from a third port for high-band.

9. The feed assembly of claim 1, wherein the respective 10-dB beamwidths for the low, mid, and high frequency bands are approximately equal.

10. The feed assembly of claim 9, wherein the respective 10-dB beamwidths are about 74 degrees.

11. The feed assembly of claim 1, further comprising a co-located phase center for transmitting signals in a low band, a mid band, and a high band.

12. A method, comprising:

receiving and transmitting signals in low, intermediate, and high frequency bands using a feed assembly for a reflector antenna;

a feed horn for providing common use of a low frequency band, a middle frequency band and a high frequency band;

receiving signals in a low frequency band using a coaxial polarizer and a coaxial orthomode transducer (OMT), wherein each of the coaxial polarizer and the coaxial OMT supports a mid-band and a high frequency band; and

signals in the mid-band and the high-band are transmitted using a multi-rod and a duplexer, wherein the multi-rod and the duplexer support the low-band.

13. The method of claim 12, further comprising providing the coaxial polarizer with a length corresponding to half a wavelength of an operating frequency in the low frequency band.

14. The method of claim 13, wherein the length of the coaxial polarizer corresponds to a property of a material forming the coaxial polarizer and a shape of the coaxial polarizer.

15. The method of claim 12, further comprising forming a portion of the coaxial polarizer that also has a notched rectangular shape.

16. The method of claim 12, further comprising positioning the first port and the second port of the coaxial OMT at a predetermined distance corresponding to a return loss threshold and an isolation threshold of the reflector antenna.

17. The method of claim 12, further comprising providing a polarizer in the center conductor of the feed assembly, the polarizer being common to the mid-band and the high-band.

18. The method of claim 12, wherein the diplexer is configured to separate two ports for mid-band from a third port for high-band.

19. The method of claim 12, wherein the respective 10-dB beamwidths for the low, mid, and high frequency bands are approximately equal.

20. The method of claim 12, further comprising co-located phase centers for transmitting signals in a low frequency band, a mid frequency band, and a high frequency band.

Background

As is known in the art, conventional SATCOM terminals utilize small or low profile reflector antennas in applications with significant size limitations. Compact or low-profile reflector antennas typically include a feed assembly that transmits signals from a transmitter or receives signals to a receiver in a corresponding antenna system. However, the size of the feed assembly may limit the type of SATCOM application in which a compact or low profile reflector antenna may be used. Furthermore, many feed assemblies are only configured to provide and support single or dual band operation.

Disclosure of Invention

The concepts, systems, and techniques disclosed herein provide a compact tri-band feed assembly that operates at first, second, and third frequency bands (e.g., low, mid, and high frequency bands) and may be used in various reflector antenna applications. The tri-band feed assembly includes various components to provide a feed assembly having smaller dimensions than feed assemblies known in the art. For example, in some embodiments, the feed assembly comprises: a compact feed horn and compact matching section supporting low, mid and high frequency bands; a coaxial polarizer and an orthomode transducer (OMT) supporting signals in a low frequency band; multiple rods and polarizers in the center conductor using circular waveguides to support signals in the mid and high frequency bands; and a diplexer to separate one or more mid-band ports from high-band ports. Thus, the feed assembly provides a tri-band feed assembly with different portions to support signals in the low band as well as signals in the mid and high bands.

The tri-band feed assembly may be designed for relatively small or low profile reflector antennas for applications having limited space for the respective reflector antenna, such as, but not limited to, airborne, shipborne, or terrestrial mobile platforms. The components of the tri-band feed assembly may have smaller (e.g., compact) dimensions than comparable components of other feed assemblies known in the art. For example, the length of the coaxial polarizer may be approximately equal to half the wavelength at the operating frequency in the low frequency band. In one embodiment, the on-axis polarizer includes one or more portions having a notched rectangular shape. In some embodiments, the reduced size may be achieved based at least in part on the properties of the one or more portions having the notched rectangular shape and the properties of the material used to form the coaxial polarizer.

The OMT may have compact dimensions such that the two low band ports are arranged very close but orthogonal to each other. In a coaxial waveguide, a pair of shorting tabs (shorting fins) is used to provide additional isolation between two orthogonal ports. The distance between the two ports may be adjusted based on a return loss threshold (return loss threshold) and an isolation threshold (isolation threshold) of the respective reflector antenna.

Two key challenges for multiband feed design of reflector antennas are having similar beamwidths and having a common phase center for all bands. With different beamwidths, the illumination or spill efficiency (spollover efficiency) of the antenna will be affected. Without a common phase center, the phase efficiency of the antenna will be affected. The physical property of the feed horn is that it typically has a wider beamwidth at lower frequencies and it becomes narrower as the frequency increases. The phase center position of most feed horns also varies with frequency. In an embodiment, the respective beamwidths of the feeding assemblies are approximately equal at each of the low, mid and high frequency bands. For example, in some embodiments, the beamwidth (e.g., 10-db beamwidth) for each of the low, medium, and high frequency bands may be about 74 degrees. In an embodiment, the feed assembly has a common phase center for each of the low, medium and high frequency bands to provide high antenna efficiency in each of the low, medium and high frequency bands.

The systems described herein may include one or more of the following features, either alone or in combination with one another.

In a first aspect, there is provided a feed assembly for a reflector antenna, the feed assembly having: a feed horn common to the low, medium and high frequency bands; a coaxial polarizer to transmit signals in a low band and to support a middle and high frequency band; a coaxial Orthogonal Mode Transducer (OMT) to transmit signals in a low frequency band and support medium and high frequency bands; and a plurality of rods provided in the center conductor of the feeding member, the plurality of rods being common to the medium and high frequency bands and supporting the low frequency band.

The length of the coaxial polarizer may correspond to half the wavelength at the operating frequency in the low frequency band. In some embodiments, the length of the coaxial polarizer corresponds to the properties of the material forming the coaxial polarizer and the shape of the coaxial polarizer. The coaxial polarizer may include a portion having a notched rectangular shape.

The coaxial OMT may further comprise at least two ports disposed a predetermined distance apart from each other. The predetermined distance may correspond to a return loss threshold and an isolation threshold of the reflector antenna.

The feed assembly may include a matching section coupled to a feed horn that is common to the low, mid, and high frequency bands. A polarizer may be provided in the center conductor of the feed assembly, which is common to the mid and high frequency bands. The feed component may include a diplexer configured to separate the first and second ports for the mid-band from the third port for the high-band.

In one embodiment, the respective beamwidths (e.g., 10-dB beamwidths) for the low, mid, and high frequency bands are approximately equal. For example, the respective beamwidths of 10-dB may be about 74 degrees. The feed assembly may include a co-located phase center for transmitting signals in the low, medium and high frequency bands.

In another aspect, a method is provided, the method comprising: receiving and transmitting signals in low, medium and high frequency bands using a feed assembly for a reflector antenna; providing a feed horn common to the low, medium and high frequency bands; transmitting a signal in a low frequency band using a coaxial polarizer and a coaxial orthomode transducer (OMT); and transmitting signals in the mid and high frequency bands using a multi-rod and duplexer, wherein the multi-rod and duplexer support the low frequency band.

The method can comprise the following steps: a coaxial polarizer is provided, the length of which corresponds to half the wavelength of the operating frequency in the low frequency band. In some embodiments, the length of the coaxial polarizer corresponds to the properties of the material forming the coaxial polarizer and the shape of the coaxial polarizer.

A portion of the coaxial polarizer may be formed to have a notched rectangular shape. The first port and the second port may be disposed at predetermined distances corresponding to a return loss threshold and an isolation threshold of the reflector antenna.

In some embodiments, a polarizer may be provided in the center conductor of the feed assembly. The polarizer may be common to both the mid and high bands. The diplexer may be configured to separate the first two ports for the mid-band from the third port for the high-band.

The respective 10-dB beamwidths of the low, mid, and high frequency bands may be approximately equal. In some embodiments, the respective beamwidths are about 74 degrees. The feed assembly may be configured to have a co-located phase center for transmitting signals in the low, medium and high frequency bands.

It is to be understood that elements of different embodiments described herein may be combined to form other embodiments not specifically set forth above. Elements described in the context of a single embodiment may also be provided separately or in suitable combination. Other embodiments not specifically described herein are also within the scope of the following claims.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

Drawings

Fig. 1 is a cross-sectional view of a tri-band feed assembly;

1A-1B are two isometric views of the tri-band feed assembly of FIG. 1;

fig. 2 is a cross-sectional view of two coaxial polarizers and a coaxial orthomode transducer (OMT) of the tri-band feed assembly of fig. 1;

2A-2B are cross-sectional views of the coaxial polarizer of the tri-band feed assembly of FIG. 1;

2C-2D are isometric views of a coaxial OMT of the tri-band feed assembly of FIG. 1;

FIGS. 2E-2F are cross-sectional views of the OMT of the tri-band feed assembly of FIG. 1;

fig. 2G is a cross-sectional view of a center conductor disposed within the coaxial OMT of the tri-band feed assembly of fig. 1;

3-3B are different views of the tri-band feed assembly of FIG. 1 coupled to a reflector antenna; and

fig. 4 is a flow chart of a method of receiving and/or transmitting signals using the tri-band feed assembly of fig. 1.

Like reference symbols in the various drawings indicate like elements.

Detailed Description

Described herein is a triple-band feed assembly for operation at a plurality of different frequency bands (e.g., low, mid, and high frequency bands) that may be used in various satellite communications (SATCOM) applications, such as reflector antenna applications. In an embodiment, the tri-band feed assembly comprises a plurality of sections having smaller (or compact) dimensions compared to similar components of other feed assemblies known in the art. Accordingly, the tri-band feed assembly may be applied to small or low profile reflector antenna applications, such as, but not limited to, airborne, shipboard, or terrestrial mobile platforms with limited real estate (real estate). Different components of the tri-band feed assembly may be configured to support one or more different frequency bands such that the respective beamwidths of the different frequency bands are approximately equal and a common phase center is maintained for each of the different frequency bands.

In an embodiment, the low, medium and high frequency bands constituting the three bands of feeds include K (20.2-21.2GHz), Ka (30-31GHz) and Q (43.5-45.5GHz) bands, respectively. It should be appreciated that although a tri-band feed is described herein, it should be understood that additional bands may use one or more components of the tri-band feed assembly described herein. The terms "common (shared)" and "support" may refer to the ability of components of the feed assembly to operate on, receive, and/or transmit signals in the respective frequency bands. In some embodiments, the operations may include transmitting or converting the signal to other components in the feed assembly. The components of the feed assembly may include, but are not limited to, a feed horn, a matching section, a coaxial polarizer, a coaxial OMT, a polarizer, a diplexer and a center conductor.

Referring now to fig. 1, a tri-band feed assembly 100 includes a feed horn 102, a matching section 104, a coaxial polarizer 106, a coaxial orthomode transducer (OMT)108, a multi-rod 110, a polarizer 112, and a duplexer 114. In the illustrated embodiment, the low, mid, and high frequency bands that make up the three bands of feeds include the K (20.2-21.2GHz), Ka (30-31GHz), and Q (43.5-45.5GHz) bands, respectively.

The feed horn 102 may be coupled to a reflector antenna (not shown), such as the reflector antenna 302 of fig. 3. In one embodiment, the feed horn 102 may receive signals from a reflector antenna and transmit the signals to other components within the feed assembly 100. The feed horn 102 may comprise a tri-band feed horn and may be configured to receive and transmit signals in the low, mid, and high frequency bands.

The matching section 104 may be disposed in the interior cavity/passageway of the feed horn 102. In one embodiment, matching section 104 may comprise a dielectric ring sandwiched between two metal iris rings to provide impedance matching between the feed and free space of the location where the transmitted signal is radiated into or the received signal comes from. The matching section 104 is configured to support each of the low, medium, and high frequency bands.

A coaxial polarizer 106 is disposed within the interior cavity of feed assembly 100 and is configured to transmit signals in the low frequency band. In some embodiments, one or more coaxial polarizers are coupled to the center conductor 116 disposed in the inner cavity of the feed assembly 100. The length of the coaxial polarizer 106 may be half the wavelength of the frequency in the low band (e.g., the operating frequency). The length may correspond to the properties of the material forming the coaxial polarizer and the shape of the coaxial polarizer. The in-line polarizer 106 will be described in more detail with reference to fig. 2-2A below.

The coaxial OMT 108 is coupled to the feed horn 102 and may be disposed about the center conductor 116 and the coaxial polarizer 106. The coaxial OMT 108 may include one or more ports (one port 124 is shown here) to transmit signals in the low frequency band. In some embodiments, the ports may include left-handed and/or right-handed circularly polarized ports. The coaxial OMT 108 may be formed to have a compact shape so that the ports may be disposed at a reduced distance from each other. The reduced (or predetermined) distance may be selected based at least in part on a return loss threshold and an isolation threshold of the reflector antenna. The coaxial OMT 108 may include a pair of shorting tabs to provide additional isolation between the two orthogonal ports. In each of the two orthogonal ports, a tapered section is used to provide a compact transition from the coaxial waveguide to the rectangular waveguide, which also serves as a matching section for the transition. The coaxial OMT 108 will be described in more detail with reference to fig. 2 and 2C-2D below.

The multiple rods 110 are disposed within the center conductor 116. In the embodiment shown in fig. 1, the multi-bar 110 is disposed within a first (end) portion 116a of the center conductor 116 such that the first end 110a extends into the feed horn 102 to emit signals from the center conductor 116, and the second end 110b is disposed adjacent the polarizer 112. The second end 110b may begin within a tapered circular waveguide portion that is reduced in diameter by the dielectric load provided by the multi-rods. In one embodiment, the dielectric load may be utilized to support an appropriate inner diameter for the coaxial waveguide. The multiple rods 110 may be configured to transmit signals in the mid and high frequency bands.

The polarizer 112 is disposed within a second (middle) portion 116b of the center conductor 116. The polarizer 112 may be configured to transmit signals in the intermediate and high frequency bands. The polarizer 112 may be configured to convert a linearly polarized wave into a circularly polarized wave, or convert a circularly polarized wave into a linearly polarized wave. The polarizer 112 may be configured to apply a phase difference or phase shift (e.g., a 90 ° phase shift) for the conversion. The polarizer 112 may be configured to transmit signals in the intermediate and high frequency bands.

The duplexer 114 may be disposed near the polarizer 112 and may be configured to transmit signals in the middle and high frequency bands. In one embodiment, third (end) portion 116c of center conductor 116 may be disposed within duplexer 114 and extend through duplexer 114. As known in the art, a waveguide duplexer is a device for combining/separating multi-band and multi-port signals to provide band or polarization identification. Duplexer 114 may include one or more ports to separate mid-band ports and high-band ports to transmit signals in the respective bands. For example, and as shown in fig. 1, duplexer 114 may include two first ports 120 (although one port is shown for clarity) for signals in the mid-band and a third port (e.g., second port 122 of fig. 1B) for signals in the high-band. It should be appreciated that the number of ports and the nature of the duplexer can be based, at least in part, on the particular application at the feed assembly 100. For example, in one embodiment, the diplexer may comprise a four-port diplexer to separate two mid-band ports from two high-band ports.

Referring briefly to fig. 1A-1B, an alternative view of the feed assembly 100 is provided showing the entire feed assembly coupled together (i.e., two portions of the feed assembly 100 coupled together). As shown in fig. 1A-1B, a feed horn 102, a coaxial OMT 108 having a port 126, and a duplexer 114 having a first port 120 (e.g., a mid-band port) and a second port 122 (e.g., a high-band port) are shown. The matching section 104, coaxial polarizer 106, multi-rods 110, polarizer 112, and center conductor 116 are not shown in fig. 1A-1B because they are disposed in the interior cavity of the feed assembly 100.

Referring now to fig. 2-2C, a first and second coaxial polarizer 202a and 202b are coupled to a coaxial OMT204 having a first OMT port 206 and a second OMT port 208. The in- line polarizers 202a, 202b and the in-line OMT204 are the same as or substantially similar to the in-line polarizer 106 and the in-line OMT 108 of fig. 1, respectively.

The first and second coaxial polarizers 202a, 202b and the coaxial OMT204 may be provided with compact dimensions compared to other polarizers and OMTs known in the art. In an embodiment, the length of each of the first and second coaxial polarizers 202a, 202b may be about half a wavelength at a frequency in the low frequency band (e.g., the operating frequency). The reduced length may be based at least in part on the shape of the respective coaxial polarizer 202a, 202b and/or the properties of the material forming the respective coaxial polarizer 202a, 202 b. For example, as is known in the art, a leaf polarizer may utilize a tapered shape to provide good impedance matching while slowing the E-field to provide a 90 degree phase shift. However, the first and second coaxial polarizers 202a, 202b (as well as other polarizers) include notched regions (as well as other polarizers described herein having notched shapes or notched regions). The notch shape may provide sufficient phase shift and/or good matching in a polarizer of shorter length than a polarizer without a notch shape. It will be appreciated that the recessed region may have more dielectric material than, for example, the tapered portion, for the same length. Accordingly, the overall length of the first and second coaxial polarizers 202a, 202b may be reduced by including one or more notched regions. In addition, the first and second coaxial polarizers 202a, 202b may comprise a high-K dielectric material (e.g., Hi-K material) having a high dielectric constant to further shorten their respective lengths from other types of blade polarizers having materials with dielectric constants from 2.1 to 2.54 (e.g., Rexolite or Teflon).

For example, and referring now to fig. 2A-2B, the same coaxial polarizer 202 as the first and second coaxial polarizers 202A, 202B of fig. 2 is shown as having a rectangular shape and including a first portion 210a, a second portion 210B, and a third portion 210 c. The first and third portions 210a, 210c (or end portions) may include notched regions (or notched rectangular regions) 212a, 212b, respectively. The second portion 210b (or intermediate portion) may be formed in a generally rectangular shape and couple the first and third portions 210a, 210 c. In one embodiment, the shape of the notched regions (i.e., the notch shape) of the first and second in- line polarizers 202a, 202b may provide sufficient phase shift and good matching in a shorter length than polarizers without notch shapes.

The coaxial polarizer 202 may include one or more materials having a high dielectric constant, such as, but not limited to, a high-K dielectric material (e.g., a Hi-K material) having a high dielectric constant.

Referring now to fig. 2C-2D, different views of the coaxial OMT204 are provided without attached ports (e.g., the first port 206 and the second port 208 of fig. 2). As shown in fig. 2B, coaxial OMT204 includes a first lumen 212, a second lumen 214, and a hollow region 216 formed within and extending the length of coaxial OMT 204. The first and second cavities 212, 214 may be configured to couple with and receive ports, such as the first and second ports 206, 208 of fig. 2. In one embodiment, the first cavity 212 and the second cavity 214 may be communicatively coupled with the hollow region 216 to transmit and receive signals in a low frequency band.

Referring now to fig. 2E-2F, first and second halves 204a, 204b of coaxial OMT204 are shown. Each of the first and second halves 204a, 204b includes a half of a first cavity 212 coupled with a first port (e.g., first port 206 of fig. 2) and receiving the first port and a half of a second cavity 214 receiving a second port (e.g., second port 208 of fig. 2). The first and second halves 204a, 204b also include halves of the hollow region 216 (here having a generally cylindrical shape) such that when the first and second halves 204a, 204b are coupled together, the hollow region 216 of fig. 2C-2D is formed. The hollow region 216 may be configured to retain a center conductor of the feed assembly. For example, and as shown in fig. 2G, the center conductor 220 may be disposed within the hollow region 216 of the coaxial OMT 204. The first and second coaxial polarizers 202a, 202b are coupled to an outer surface of the center conductor 220.

Referring back now to fig. 2, the coaxial OMT204 may be formed such that the first port 206 and the second port 208 are disposed a predetermined distance apart from each other. The predetermined distance may be based at least in part on a return loss threshold and an isolation threshold of a reflector antenna to which the coaxial OMT204 is coupled. In one embodiment, the total length of the coaxial OMT204 may be about 1.75 wavelengths in the low frequency band, and the separation between the two ports (i.e., the first and second ports 206, 208) may be less than 0.4 wavelengths. However, it should be understood that the overall length of the coaxial OMT204 and the spacing between the two ports may vary based at least in part on the requirements of a particular application.

Referring now to fig. 3-3B, different views of reflector antenna 302 are shown coupled to feed assembly 306. The feed assembly 306 includes a feed horn 308, a matching section 310, a coaxial polarizer 312, a coaxial OMT 314, a multi-rod 316, a polarizer 318, a diplexer 320, and a center conductor 322. The feed assembly 306 may be the same as or substantially similar to the feed assembly 100 of fig. 1.

The feed component 306 may be coupled to the reflector antenna 302 to provide a tri-band feed such that the reflector antenna 302 may transmit and/or receive signals in multi-bands (e.g., low, mid, and high bands). In one embodiment, the feed assembly 306 may be configured to have a common phase center for each different frequency band and achieve high phase efficiency for the reflector antenna 302 for all three frequency bands. The feed element 302 may have an equal or substantially equal beamwidth for each of the different frequency bands. In some embodiments, the 10-dB beamwidth for the different frequency bands may be about 10dB, and may be about 74 degrees.

Referring now to fig. 4, a flow diagram of a method 400 of receiving and/or transmitting signals using the tri-band feed assembly 100 of fig. 1 begins at block 402, where signals are received and transmitted in low, mid, and high frequency bands by using the feed assembly for a reflector antenna. The feed assembly may be coupled to the reflector antenna and configured to support signals in each of the low, medium, and high frequency bands (e.g., the low-K (20.2-21.2GHz), medium-Ka (30-31GHz), and high-Q (43.5-45.5GHz) bands).

At block 404, a feed horn common to the low, mid, and high frequency bands may be provided. The feed assembly may include a feed horn coupled to the reflector antenna. The feed horn may be configured to emit signals in each of the low, medium and high frequency bands, thereby conveying (or transmitting) signals received by the reflector antenna to other components within the feed assembly.

The matching section is coupled to the feed horn. The matching section may be configured to process signals in each of the low, medium and high frequency bands and transmit them to the coaxial polarizer and coaxial OMT of the feeding assembly.

At block 406, signals in the low frequency band may be transmitted using the coaxial polarizer and the coaxial OMT. The coaxial polarizer may apply a phase difference to the received signal for polarization conversion.

In some embodiments, one or more coaxial polarizers may be disposed on the outer surface of the center conductor. The coaxial polarizer and the center conductor may be disposed within the inner cavity of the coaxial OMT. The coaxial OMT may include a plurality of ports to transmit signals in a low frequency band. For example, in some embodiments, a coaxial OMT may include a first port for signals having left-hand circular polarization properties and a second port for signals having right-hand circular polarization properties.

At block 408, signals in the mid-band and the high-band may be transmitted using the multi-rods and the duplexer. Signals having frequencies corresponding to the mid-band or high-band are received at the multiple rods. The multiple rods may be disposed in the center conductor of the feed assembly such that the first end extends to the feed horn to receive the signal and the second end is disposed in the approximate middle of the center conductor to transmit the signal to other components (e.g., polarizer, diplexer) in the feed assembly. Each of the first and second ends of the multi-bar may include a tapered portion. The tapered portion of the multi-rod may provide a gradual impedance change to minimize mismatch of both the mid-band and the high-band. Thus, the multiple rods may be configured to support signals in the mid-band and high-band and transmit them to the polarizer.

The polarizer may be configured to support and transmit signals in the intermediate and high frequency bands to the duplexer. The duplexer may include a plurality of ports to separate signals in the middle frequency band from signals in the high frequency band. In some embodiments, the duplexer may include at least one mid-band output port and at least one high-band output port. The mid-band output port may transmit signals in the mid-band, while the high-band output port may transmit signals in the high-band.

The feed assembly supports and transmits signals in each of the low, mid, and high frequency bands by including a portion for low frequency band signals and a portion for mid and high frequency band signals. For example, and as described herein, the coaxial polarizer and coaxial OMT may be configured to transmit signals in a low frequency band, while the multi-rods, polarizer, and duplexer may be configured to transmit signals in a mid-band and a high frequency band. Thus, the feeding assembly is a tri-band feeding assembly.

Having described preferred embodiments for illustrating the various concepts, structures and techniques of the inventive subject matter, it will now become apparent that other embodiments can be used that combine these concepts, structures and techniques. Accordingly, the scope of patented should not be limited to the described embodiments, but should be defined only by the spirit and scope of the appended claims.

Accordingly, other embodiments are within the scope of the following claims.