Multi-band antenna for simultaneously communicating linear polarity and circular polarity signals

Multi-band antennas for simultaneously communicating linear polarity low-band signals and circular polarity high-band signals via a single antenna horn structure. The antennas horn structures have circular and oblong cross-sections. Strategic location and orientation of low-band and high-band ports with respect to internal ridges in transition sections and the major and minor axes of the oblong horn allows the antenna to simultaneously manipulate the high-band circular polarity signal without affecting the linear polarity low-band signals. The oblong horn shape and ridges may apply additive or oppositely sloped differential phase shifts to the linear components of the circular polarity high-band signal. For the horns with circular cross-section, the internal ridges may apply additive or oppositely sloped differential phase shifts to polarize the circular polarity high band signals without assistance from the internal shape of the horn.

TECHNICAL FIELD

The present invention is generally related to multi-band antenna systems designed to simultaneously receive broadcast signals with circular and linear polarity and, more particularly, is directed to digital video broadcast satellite (DVBS) antenna systems.

BACKGROUND OF THE INVENTION

DVBS antenna systems for communicating with satellites are becoming increasingly complex. Quite often a given reflector antenna must be configured to simultaneously receive and transmit signals to multiple satellites. These satellites typically operate at different frequency bands and often with different polarities, making the feed assembly challenging to design and cost effectively produce and deploy in large quantities.

The antenna designs described in U.S. Pat. Nos. 7,239,285 and 7,642,982 address many of these challenges for oblong and circular antenna feed structures for receiving multi-band circular polarity signals. Although the antenna technology described in these patents is applicable to DVBS antennas generally, these patents have not disclosed multi-band antennas for simultaneously receiving combinations of linear polarity and circular polarity signals.

SUMMARY OF THE INVENTION

The present invention addresses the needs described above in a variety of multi-band antennas for simultaneously communicating combinations of linear polarity and circular polarity signals. The specific embodiments shown in the figures are designed to receive linear polarity low-band signals simultaneously with circular polarity high-band signals via a single antenna horn structure. Embodiments of the antennas horn structures have circular and oblong cross-sections. In general, strategic location and orientation of low-band and high-band ports with respect to internal ridges that form phase adjustment structures in transition sections and the major and minor axes of the oblong horn allows the antenna to simultaneously manipulate the high-band circular polarity signal without affecting the linear polarity low-band signals. For the horns with circular cross-section, the internal ridges polarize the circular polarity high band signals without assistance from the internal shape of the horn.

The oblong horn structures are phase adjustment structures configured to differentially phase shift the linear components of the circular polarity high-band signal without affecting the linear polarity low-band signals. For the horns with oblong cross-section, the internal oblong shape of the horn, alone or in combination with internal ridges, polarize the circular polarity high band signals. Over the full length of the antenna horn, the oblong horns and the ridges in combination serve to differentially phase shift and polarize the linear components of the circular polarity high-band signal by approximately 90 degrees to polarize the circular polarity high-band signal into linear components. Most of the embodiments include transition sections with ridges that form phase adjustment structures that operate in combination with the shape of the horn to polarize the circular polarity high-band signals without affecting the linear polarity low-band signals. In certain embodiments, the oblong horn and ridges impart oppositely sloped phase differential sections to improve the high-band gain and bandwidth performance of the antenna as described in U.S. Pat. Nos. 7,239,285 and 7,642,982.

Although the specific embodiments involve linear polarity low-band signals and circular polarity high-band signals, the principles of the invention are not limited to these configuration and could be applied, for example, to construct antennas that simultaneously communicate circular polarity low-band signals and linear polarity high-band signals. Similarly, the specific embodiments involve one low-band dual-polarity signal and one high-band circular polarity signal that is polarized into linear components, but could be applied to signals-polarity signals and a larger number of signals matters of design choice and the needs of specific applications.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention may be embodied as improvements to the multi-band DVBS antennas described in U.S. Pat. Nos. 7,239,285 and 7,642,982, which are incorporated herein by reference. These patents teach the use of oppositely sloped phase differential transition sections including various combinations of internal ridges (including septums and corrugations, which are varieties of internal ridges) with oblong and circular horns to improve the bandwidth performance of the antennas. They also disclose multi-band antennas using these techniques for multiple circular polarity signals but do not disclose multi-band antennas for receiving combinations of linear polarity and circular polarity signals. Simultaneously communicating circular and linear polarity signals is challenging because the structures of the antennal must be designed to simultaneously polarize the circular polarity signals without adversely affecting the linear polarity signals. The embodiments of the present invention meet the challenge with cost effective, high performance antennas that transmit and receive multiple bands using multiple polarities.

The present invention develops multi-band antennas for simultaneously communicating linear polarity low-band signals and circular polarity high-band signals via a single antenna horn structure. Various antennas horn structures have circular and oblong cross-sections. Strategic location and orientation of low-band and high-band ports with respect to internal ridges in transition sections and the major and minor axes of the oblong horn allows the antenna to simultaneously manipulate the high-band circular polarity signal without affecting the linear polarity low-band signals. The oblong horn shape and ridges may apply additive or oppositely sloped differential phase shifts to the linear components of the circular polarity high-band signal. For the horns with circular cross-section, the internal ridges may apply additive or oppositely sloped differential phase shifts to polarize the circular polarity high band signals without assistance from the internal shape of the horn.

The specific embodiments shown in the figures are designed to simultaneously communicate low-band signals with linear polarity and high-band signals with circular polarity. Although these antennas are capable of bidirectional communications, the antennas are generally described with reference to the reception communication direction for descriptive convenience. It should be understood that the size and shape of each antenna is specifically designed for the intended operational frequencies of the antenna, but can be readily changed to be appropriate of other operational frequencies. In addition, the figures illustrate the shape of the internal surfaces (i.e., wave guide surfaces) of the antennas without illustrating any external features. Therefore, the antennas shown may be cast, cut or machined into single or multiple blocks of material (typically aluminum or zinc alloy) as desired. It will be appreciated that the internal wave guide surfaces of the antennas shown in the figures control the operational aspects of the antennas and the external features of the antennas typically provide mounting structures but have no appreciable affect on the wave guide operation of the antennas. In general, the antennas shown in the figures are described with reference to a Cartesian coordinate system5illustrated on many of the figures. In the Cartesian coordinate system, the “Z” direction represents the intended signal propagation or “bore sight” direction of the antenna as a matter of convention and reference is made to various directions and planes in the Cartesian coordinate system to aid in the description of the structures.

FIGS. 1A through 1Hillustrate a first multi-band antenna110for simultaneously communicating low-band signals with linear polarity and high-band signals with circular polarity.FIG. 1Ais perspective view of the antenna110with the “Z” direction representing the signal propagation direction of the antenna.FIG. 1Bis an “X-Z” plane side view of the antenna110,FIG. 1Cis a “Y-Z” plane side view of the antenna110, andFIG. 1Dis an “X-Y” plane top view of the antenna110. The antenna110includes a wave guide horn112extending in the signal propagation direction from a reception end114shown at the top ofFIG. 1Ato high-band port116shown at the bottom ofFIG. 1A. The wave guide horn112includes a first transition section118with an upper reception section119having an oblong, generally elliptical cross-section transverse to the signal propagation direction (i.e., an oblong or elliptical shape in the “X-Y” plane) that decreases in oblong extent until it merges into a circular profile. The oblong cross-section is defined by a major axis in the “X” direction and a minor axis in the “Y” direction.

The first transition section118extends from the reception end114to low-band ports120,122. The first low-band port120lies in the “X-Z” plane and leads to a first low-band wave guide124for communicating a first linear polarity (e.g., horizontal or “H” polarity) of the low-band signal. The second low-band port122lies in the “Y-Z” plane and leads to a second low-band wave guide126for communicating a second linear polarity (e.g., vertical or “V” polarity) of the low-band signal. The first low-band wave guide124includes a high-band rejection filter134to prevent the high-band signal from propagating through the low-band wave guide124, and the second low-band wave guide126includes a high-band rejection filter136to prevent the high-band signal from propagating through the low-band wave guide126. As the first transition section118is located between the reception end114and the low-band ports120,122(i.e., above the low-band ports), both the high-band and low-band signals propagate through the first transition section118.

The horn112further includes a second transition section130that extends from below the low-band ports120,122to the high-band port116. As the second transition section130is located between the low-band ports120,122and the high-band port116, (i.e., below the low-band ports), only the high-band signal propagate through the second transition section130. It should be noted here that a specific structure for the high-band port116is not illustrated and is typically implemented in a structure immediately following the high-band port116, such as a high-band wave guide, low-noise amplifier, or other suitable structure. Any type of suitable high-band pickups may be used, such as probes, wave guide openings, a wave guide divided by a septum, and so forth.

FIG. 1Bshows that the major axis of the reception section119flairs substantially in the “X” direction, whileFIG. 1Cshows that the minor axis of the reception section does not flair substantially in the “Y” direction.FIG. 1Eis a conceptual “X-Y” plane top view of the antenna110illustrating the locations and orientations of the high-band and low-band ports. The first low-band output port120is aligned in the “X” direction and the second low-band output port122is aligned in the “Y” direction. As a result, the decreasing oblong shape of the reception section119does not affect the polarity of the linear polarity low-band signal. The high-band output ports140,142, on the other hand, are aligned at 45 degrees to the “Y” and “X” axes, respectively. The decreasing oblong shape of the reception section119therefore differentially phase shifts the linear components of the circular polarity high-band signal as the signal propagates through the oblong reception section119. The length, shape and taper of the reception section119is specifically designed to impart a desired amount of differential phase shift to the linear components of the circular polarity high-band signal as the high-band signal propagates through the oblong reception section119.

In this particular embodiment, the oblong reception section119imparts 130 degrees of differentially phase shift to the linear components of the circular polarity high-band signal and the second transition section130includes a set of ridges132that impart 40 degrees of differentially phase shift to the linear components of the circular polarity high-band signal in the opposite direction (i.e., negative 40 degrees, or 40 degrees oppositely sloped) for a total of 90 degrees, which polarizes the circular polarity high-band signal into linear polarities at the high-band port116. “Over rotation” of the differential phase shift in the oblong reception section119followed by “oppositely sloped” rotation in the reverse direction in the lower transition section530improves the high-band gain and bandwidth performance of the antenna, as described in U.S. Pat. Nos. 7,239,285 and 7,642,982.

FIG. 1Fis a conceptual “X-Y” plane top view of the multi-band antenna110illustrating the location of section lines A-A and B-B.FIG. 1Gis an “X-Z” plane cross-section side view illustrating internal features of the transition section130as viewed along section line A-A andFIG. 1His a “Y-Z” plane cross-section side view further illustrating the internal features of the transition section130as viewed along section line B-B. In this particular embodiment, the ridges132lie in the “X-Z” plane and are aligned in the “X” direction. The size, shape and locations of the ridges are specifically designed to impart the desired differential phase shift to the linear components of the circular polarity high-band signal as the high-band signal propagates through the second transition section130.

FIGS. 2A through 2Hillustrate a second multi-band antenna210for simultaneously communicating low-band signals with linear polarity and high-band signals with circular polarity.FIG. 2Ais perspective view of the antenna210with the “Z” direction representing the signal propagation direction of the antenna.FIG. 2Bis an “X-Z” plane side view of the antenna210,FIG. 2Cis a “Y-Z” plane side view of the antenna210, andFIG. 2Dis an “X-Y” plane top view of the antenna210. The antenna210includes a wave guide horn212extending in the signal propagation direction from a reception end214shown at the top ofFIG. 2Ato high-band port216shown at the bottom ofFIG. 2A. The wave guide horn212includes a first transition section218with an upper reception section219having an oblong cross-section transverse to the signal propagation direction (i.e., an oblong shape in the “X-Y” plane) that decreases in oblong extent until it merges into a circular profile. The oblong cross-section is defined by a major axis in the “X” direction and a minor axis in the “Y” direction.

The first transition section218extends from the reception end214to low-band ports220,222. The first low-band port220lies in the “X-Z” plane and leads to a first low-band wave guide224for communicating a first linear polarity (e.g., horizontal or “H” polarity) of the low-band signal. The second low-band port222lies in the “Y-Z” plane and leads to a second low-band wave guide226for communicating a second linear polarity (e.g., vertical or “V” polarity) of the low-band signal. The first low-band wave guide224includes a high-band rejection filter234to prevent the high-band signal from propagating through the low-band wave guide224, and the second low-band wave guide226includes a high-band rejection filter236to prevent the high-band signal from propagating through the low-band wave guide226. As the first transition section218is located between the reception end214and the low-band ports220,222(i.e., above the low-band ports), both the high-band and low-band signals propagate through the first transition section218.

The horn212further includes a second transition section230that extends from below the low-band ports220,222to the high-band port216. As the second transition section230is located between the low-band ports220,222and the high-band port216, (i.e., below the low-band ports), only the high-band signal propagate through the second transition section230. It should be noted here that a specific structure for the high-band port216is not illustrated and is typically implemented in a structure immediately following the high-band port216, such as a high-band wave guide, low-noise amplifier, or other suitable structure. Any type of suitable high-band pickups may be used, such as probes, wave guide openings, a wave guide divided by a septum, and so forth.

FIG. 2Bshows that the major axis of the reception section219flairs substantially in the “X” direction, whileFIG. 2Cshows that the minor axis of the reception section does not flair substantially in the “Y” direction.FIG. 2Eis a conceptual “X-Y” plane top view of the antenna210illustrating the locations and orientations of the high-band and low-band ports. The first low-band output port220is aligned in the “X” direction and the second low-band output port222is aligned in the “Y” direction. As a result, the decreasing oblong shape of the reception section219does not affect the polarity of the linear polarity low-band signal. The high-band output ports240,242, on the other hand, are aligned at 45 degrees to the “Y” and “X” axes, respectively. The decreasing oblong shape of the reception section219therefore differentially phase shifts the linear components of the circular polarity high-band signal as the signal propagates through the oblong reception section219. The length, shape and taper of the reception section219is specifically designed to impart a desired amount of differential phase shift to the linear components of the circular polarity high-band signal as the high-band signal propagates through the oblong reception section219.

In this particular embodiment, the oblong reception section219imparts 60 degrees of differentially phase shift to the linear components of the circular polarity high-band signal and the second transition section230includes a set of ridges232that impart 30 degrees of differentially phase shift to the linear components of the circular polarity high-band signal in the same direction (i.e., additive 40 degrees) for a total of 90 degrees, which polarizes the circular polarity high-band signal into linear polarities at the high-band port216.

FIG. 1Fis a conceptual “X-Y” plane top view of the multi-band antenna210illustrating the location of section lines A-A and B-B.FIG. 1Gis an “X-Z” plane cross-section side view illustrating internal features of the transition section230as viewed along section line A-A andFIG. 1His a “Y-Z” plane cross-section side view further illustrating the internal features of the transition section230as viewed along section line B-B. In this particular embodiment, the ridges232lie in the “Y-Z” plane and are aligned in the “Y” direction. The size, shape and locations of the ridges are specifically designed to impart the desired differential phase shift to the linear components of the circular polarity high-band signal as the high-band signal propagates through the second transition section230.

FIGS. 3A through 3Eillustrate a third multi-band antenna310for simultaneously communicating low-band signals with linear polarity and high-band signals with circular polarity.FIG. 3Ais perspective view of the antenna310with the “Z” direction representing the signal propagation direction of the antenna.FIG. 3Bis an “X-Z” plane side view of the antenna310,FIG. 3Cis a “Y-Z” plane side view of the antenna310, andFIG. 3Dis an “X-Y” plane top view of the antenna310. The antenna310includes a wave guide horn312extending in the signal propagation direction from a reception end314shown at the top ofFIG. 3Ato high-band port316shown at the bottom ofFIG. 3A. The wave guide horn312includes a first transition section318with an upper reception section319having an oblong cross-section transverse to the signal propagation direction (i.e., an oblong shape in the “X-Y” plane) that decreases in oblong extent until it merges into a circular profile. The oblong cross-section is defined by a major axis in the “X” direction and a minor axis in the “Y” direction.

The first transition section318extends from the reception end314to low-band ports320,322. The first low-band port320lies in the “X-Z” plane and leads to a first low-band wave guide324for communicating a first linear polarity (e.g., horizontal or “H” polarity) of the low-band signal. The second low-band port322lies in the “Y-Z” plane and leads to a second low-band wave guide326for communicating a second linear polarity (e.g., vertical or “V” polarity) of the low-band signal. The first low-band wave guide324includes a high-band rejection filter334to prevent the high-band signal from propagating through the low-band wave guide324, and the second low-band wave guide326includes a high-band rejection filter336to prevent the high-band signal from propagating through the low-band wave guide326. As the first transition section318is located between the reception end314and the low-band ports320,222(i.e., above the low-band ports), both the high-band and low-band signals propagate through the first transition section318.

The horn312further includes a second transition section330that extends from below the low-band ports320,322to the high-band port316. As the second transition section330is located between the low-band ports320,322and the high-band port316, (i.e., below the low-band ports), only the high-band signal propagate through the second transition section330. It should be noted here that a specific structure for the high-band port316is not illustrated and is typically implemented in a structure immediately following the high-band port316, such as a high-band wave guide, low-noise amplifier, or other suitable structure. Any type of suitable high-band pickups may be used, such as probes, wave guide openings, a wave guide divided by a septum, and so forth.

FIG. 3Bshows that the major axis of the reception section319flairs substantially in the “X” direction, whileFIG. 2Cshows that the minor axis of the reception section does not flair substantially in the “Y” direction.FIG. 2Eis a conceptual “X-Y” plane top view of the antenna310illustrating the locations and orientations of the high-band and low-band ports. The first low-band output port320is aligned in the “X” direction and the second low-band output port322is aligned in the “Y” direction. As a result, the decreasing oblong shape of the reception section319does not affect the polarity of the linear polarity low-band signal. The high-band output ports340,342, on the other hand, are aligned at 45 degrees to the “Y” and “X” axes, respectively. The decreasing oblong shape of the reception section319therefore differentially phase shifts the linear components of the circular polarity high-band signal as the signal propagates through the oblong reception section319. The length, shape and taper of the reception section319is specifically designed to impart a desired amount of differential phase shift to the linear components of the circular polarity high-band signal as the high-band signal propagates through the oblong reception section319.

In this particular embodiment, the oblong reception section319imparts 90 degrees of differentially phase shift to the linear components of the circular polarity high-band signal and the second transition section330does not includes any ridges to further differentially phase shift the linear components of the circular polarity high-band signal. As a result, in this embodiment the oblong reception section319alone polarizes the circular polarity high-band signal into linear polarities at the high-band port316.

FIGS. 4A through 4Eillustrate a fourth multi-band antenna410for simultaneously communicating low-band signals with linear polarity and high-band signals with circular polarity.FIG. 4Ais perspective view of the antenna410with the “Z” direction representing the signal propagation direction of the antenna. The antenna410includes a wave guide horn412extending in the signal propagation direction from a reception end414shown at the top ofFIG. 4Ato high-band port416shown at the bottom ofFIG. 4A. The wave guide horn412includes a first transition section418with an upper reception section419having a circular cross-section transverse to the signal propagation direction that decreases in radial extent until it merges into a smaller circular profile. A wave guide section421with a substantially constant radius transverse to the signal propagation section extends from a larger reception cone to the low-band ports420,422.

The first transition section418extends from the reception end414to the low-band ports420,422. The first low-band port420lies in the “X-Z” plane and leads to a first low-band wave guide424for communicating a first linear polarity (e.g., horizontal or “H” polarity) of the low-band signal. The second low-band port422lies in the “Y-Z” plane and leads to a second low-band wave guide426for communicating a second linear polarity (e.g., vertical or “V” polarity) of the low-band signal. The first low-band wave guide424includes a high-band rejection filter434to prevent the high-band signal from propagating through the low-band wave guide424, and the second low-band wave guide426includes a high-band rejection filter436to prevent the high-band signal from propagating through the low-band wave guide426. As the first transition section418is located between the reception end414and the low-band ports420,422(i.e., above the low-band ports), both the high-band and low-band signals propagate through the first transition section418.

The horn412further includes a second transition section430that extends from below the low-band ports420,422to the high-band port416. As the second transition section430is located between the low-band ports420,422and the high-band port416, (i.e., below the low-band ports), only the high-band signal propagate through the second transition section430. In this particular embodiment, the transition section430includes a pair of ridges432(only one ridge is illustrated inFIG. 4Afor clarity, while both ridges are illustrated inFIG. 4E) that impart 90 degrees of differentially phase shift to the linear components of the circular polarity high-band signal to polarize the high-band signal as it propagates through the antenna410. It should be noted here that a specific structure for the high-band port416is not illustrated and is typically implemented in a structure immediately following the high-band port416, such as a high-band wave guide, low-noise amplifier, or other suitable structure. Any type of suitable high-band pickups may be used, such as probes, wave guide openings, a wave guide divided by a septum, and so forth.

FIG. 4Bis a conceptual “X-Y” plane top view of the antenna410illustrating the locations and orientations of the high-band and low-band ports. The first low-band output port420is aligned in the “X” direction and the second low-band output port422is aligned in the “Y” direction. The decreasing circular shape of the reception section419does not affect the polarity of the linear polarity low-band signal. The high-band output ports440,442, on the other hand, are aligned at 45 degrees to the “Y” and “X” axes, respectively. As a result, any ridges in the internal profile of the antenna that are aligned with the “X’ axis or the “Y” axis do not affect the polarity of the linearly polarity low-band signal, while they differentially phase shift the linear components of the circular polarity high-band signal as the signal propagates through the antenna. The length, shape and taper of the ridges are therefore specifically designed to impart 90 degrees of differential phase shift to the linear components of the circular polarity high-band signal to polarize the high-band signal as it propagates through the antenna410.

FIG. 4Cis a conceptual “X-Y” plane top view of the multi-band antenna410illustrating the location of section lines A-A and B-B.FIG. 4Dis an “X-Z” plane cross-section side view illustrating internal features of the transition section430as viewed along section line A-A andFIG. 4Cis a “Y-Z” plane cross-section side view further illustrating the internal features of the transition section430as viewed along section line B-B. In this particular embodiment, the ridges432lie in the “Y-Z” plane and are aligned in the “Y” direction. The size, shape and locations of the ridges are specifically designed to impart the desired 90 differential phase shift to the linear components of the circular polarity high-band signal to polarize the high-band signal as it propagates through the second transition section430.

FIGS. 5A through 5Eillustrate a fifth multi-band antenna510for simultaneously communicating low-band signals with linear polarity and high-band signals with circular polarity.FIG. 5Ais perspective view of the antenna510with the “Z” direction representing the signal propagation direction of the antenna. The antenna510includes a wave guide horn512extending in the signal propagation direction from a reception end514shown at the top ofFIG. 5Ato high-band port516shown at the bottom ofFIG. 5A. The wave guide horn512includes a first transition section518with an upper reception section519having a circular cross-section transverse to the signal propagation direction that decreases in radial extent until it merges into a smaller circular profile. A wave guide section521with a substantially constant radius transverse to the signal propagation section extends from a larger reception cone to the low-band ports520,522.

The first transition section518extends from the reception end514to the low-band ports520,522. The first low-band port520lies in the “X-Z” plane and leads to a first low-band wave guide524for communicating a first linear polarity (e.g., horizontal or “H” polarity) of the low-band signal. The second low-band port522lies in the “Y-Z” plane and leads to a second low-band wave guide526for communicating a second linear polarity (e.g., vertical or “V” polarity) of the low-band signal. The first low-band wave guide524includes a high-band rejection filter534to prevent the high-band signal from propagating through the low-band wave guide524, and the second low-band wave guide526includes a high-band rejection filter536to prevent the high-band signal from propagating through the low-band wave guide526. As the first transition section518is located between the reception end514and the low-band ports520,522(i.e., above the low-band ports), both the high-band and low-band signals propagate through the first transition section518.

The horn512further includes a second transition section530that extends from below the low-band ports520,522to the high-band port516. As the second transition section530is located between the low-band ports520,522and the high-band port516, (i.e., below the low-band ports), only the high-band signal propagate through the second transition section530. In this particular embodiment, the upper wave guide section521includes a first set of ridges540(only one ridge is illustrated inFIG. 5Afor clarity, while both ridges are illustrated inFIG. 5F), and the lower transition section430includes a second pair of ridges532(only one ridge is illustrated inFIG. 5Afor clarity, while both ridges are illustrated inFIG. 5E) that in combination impart 90 degrees of differentially phase shift to the linear components of the circular polarity high-band signal to polarize the high-band signal as it propagates through the antenna410. It should be noted here that a specific structure for the high-band port516is not illustrated and is typically implemented in a structure immediately following the high-band port516, such as a high-band wave guide, low-noise amplifier, or other suitable structure. Any type of suitable high-band pickups may be used, such as probes, wave guide openings, a wave guide divided by a septum, and so forth.

FIG. 5Bis a conceptual “X-Y” plane top view of the antenna510illustrating the locations and orientations of the high-band and low-band ports. The first low-band output port520is aligned in the “X” direction and the second low-band output port522is aligned in the “Y” direction. The decreasing circular shape of the reception section519does not affect the polarity of the linear polarity low-band signal. The high-band output ports540,542, on the other hand, are aligned at 45 degrees to the “Y” and “X” axes, respectively. As a result, any ridges in the internal profile of the antenna that are aligned with the “X′ axis or the “Y” axis do not affect the polarity of the linearly polarity low-band signal, while they differentially phase shift the linear components of the circular polarity high-band signal as the signal propagates through the antenna. The length, shape and taper of the ridges are therefore specifically designed to impart 90 degrees of differential phase shift to the linear components of the circular polarity high-band signal to polarize the high-band signal as it propagates through the antenna510.

FIG. 5Cis a conceptual “X-Y” plane top view of the multi-band antenna510illustrating the location of section lines A-A and B-B.FIG. 5Dis an “X-Z” plane cross-section side view of the lower transition section530illustrating internal features of the lower transition section as viewed along section line A-A.FIG. 5Eis a “Y-Z” plane cross-section side view of the lower transition section530further illustrating the internal features of the lower transition section as viewed along section line B-B. In this particular embodiment, the ridges532on the internal surface of the lower transition section530lie in the “Y-Z” plane and are aligned in the “Y” direction. The size, shape and locations of the ridges are specifically designed to impart the desired differential phase shift to the linear components of the circular polarity high-band signal to polarize the high-band signal as it propagates through the lower transition section530.

FIG. 5Fis an “X-Z” plane cross-section side view of the upper wave guide section521forming the lower portion of the upper transition section518illustrating internal features of the upper wave guide section as viewed along section line A-A.FIG. 5Gis a “Y-Z” plane cross-section side view of the upper wave guide section521further illustrating the internal features of the upper wave guide section as viewed along section line B-B. In this particular embodiment, the ridges540on the internal surface of the upper wave guide section521lie in the “X-Z” plane and are aligned in the “Y” direction. The size, shape and locations of the ridges are specifically designed to impart the desired differential phase shift to the linear components of the circular polarity high-band signal as it propagates through the upper wave guide section521.

In this particular embodiment, the first set of ridges540on the interior surface of the upper wave guide section521impart 130 degrees of differential phase shift to the linear components of the circular polarity high0band signal, while the second set of ridges532on the interior surface of the lower transition section530impart 40 degrees of differential phase shift to the linear components of the circular polarity high-band signal in the opposite direction (i.e., negative 40 degrees, or 40 degrees oppositely sloped) for a total of 90 degrees, which polarizes the circular polarity high-band signal into linear polarities at the high-band port516. “Over rotation” of the differential phase shift in the upper wave guide section52followed by “oppositely sloped” rotation in the reverse direction in the lower transition section530improves the high-band gain and bandwidth performance of the antenna, as described in U.S. Pat. Nos. 7,239,285 and 7,642,982.

FIGS. 6A through 6Eillustrate a sixth multi-band antenna610for simultaneously communicating low-band signals with linear polarity and high-band signals with circular polarity.FIG. 6Ais perspective view of the antenna610with the “Z” direction representing the signal propagation direction of the antenna.FIG. 6Bis an “X-Z” plane side view of the antenna610,FIG. 6Cis a “Y-Z” plane side view of the antenna610, andFIG. 6Dis an “X-Y” plane top view of the antenna610. The antenna610includes a wave guide horn612extending in the signal propagation direction from a reception end614shown at the top ofFIG. 5Ato high-band port616shown at the bottom ofFIG. 5A. The wave guide horn612includes a first transition section618with an upper reception section619having a circular cross-section transverse to the signal propagation direction that decreases in radial extent until it merges into a smaller circular profile. A wave guide section621with a substantially constant radius transverse to the signal propagation section extends from a larger reception cone to the low-band ports620,522.

The first transition section618extends from the reception end614to the low-band ports620,622. The first low-band port620lies in the “X-Z” plane and leads to a first low-band wave guide624for communicating a first linear polarity (e.g., horizontal or “H” polarity) of the low-band signal. The second low-band port622lies in the “Y-Z” plane and leads to a second low-band wave guide626for communicating a second linear polarity (e.g., vertical or “V” polarity) of the low-band signal. The first low-band wave guide624includes a high-band rejection filter634to prevent the high-band signal from propagating through the low-band wave guide624, and the second low-band wave guide626includes a high-band rejection filter636to prevent the high-band signal from propagating through the low-band wave guide626. As the first transition section618is located between the reception end614and the low-band ports620,622(i.e., above the low-band ports), both the high-band and low-band signals propagate through the first transition section618.

The horn612further includes a second transition section630that extends from below the low-band ports620,622to the high-band port616. As the second transition section630is located between the low-band ports620,622and the high-band port616, (i.e., below the low-band ports), only the high-band signal propagate through the second transition section630. In this particular embodiment, the upper wave guide section621includes a first set of ridges640(only one ridge is illustrated inFIG. 5Afor clarity, while both ridges are illustrated inFIG. 5F), and the lower transition section630includes a second pair of ridges632(only one ridge is illustrated inFIG. 5Afor clarity, while both ridges are illustrated inFIG. 5E) that in combination impart 90 degrees of differentially phase shift to the linear components of the circular polarity high-band signal to polarize the high-band signal as it propagates through the antenna610. It should be noted here that a specific structure for the high-band port616is not illustrated and is typically implemented in a structure immediately following the high-band port616, such as a high-band wave guide, low-noise amplifier, or other suitable structure. Any type of suitable high-band pickups may be used, such as probes, wave guide openings, a wave guide divided by a septum, and so forth.

FIG. 6Bis a conceptual “X-Y” plane top view of the antenna610illustrating the locations and orientations of the high-band and low-band ports. The first low-band output port620is aligned in the “X” direction and the second low-band output port622is aligned in the “Y” direction. The decreasing circular shape of the reception section619does not affect the polarity of the linear polarity low-band signal. The high-band output ports640,642, on the other hand, are aligned at 45 degrees to the “Y” and “X” axes, respectively. As a result, any ridges in the internal profile of the antenna that are aligned with the “X’ axis or the “Y” axis do not affect the polarity of the linearly polarity low-band signal, while they differentially phase shift the linear components of the circular polarity high-band signal as the signal propagates through the antenna. The length, shape and taper of the ridges are therefore specifically designed to impart 90 degrees of differential phase shift to the linear components of the circular polarity high-band signal to polarize the high-band signal as it propagates through the antenna610.

In this particular embodiment, the first set of ridges640on the interior surface of the upper wave guide section621impart 30 degrees of differential phase shift to the linear components of the circular polarity high0band signal, while the second set of ridges632on the interior surface of the lower transition section630impart 30 degrees of differential phase shift to the linear components of the circular polarity high-band signal in the same direction (i.e., additive 30 degrees) for a total of 90 degrees, which polarizes the circular polarity high-band signal into linear polarities at the high-band port616.

FIGS. 7A through 7Eillustrate a seventh multi-band antenna710for simultaneously communicating low-band signals with linear polarity and high-band signals with circular polarity.FIG. 7Ais perspective view of the antenna710with the “Z” direction representing the signal propagation direction of the antenna.FIG. 7Bis an “X-Z” plane side view of the antenna710,FIG. 7Cis a “Y-Z” plane side view of the antenna710, andFIG. 7Dis an “X-Y” plane top view of the antenna710. The antenna710includes a wave guide horn712extending in the signal propagation direction from a reception end714shown at the top ofFIG. 7Ato high-band port716shown at the bottom ofFIG. 7A. The wave guide horn712includes a first transition section718with an upper reception section719having a circular cross-section transverse to the signal propagation direction that decreases in radial extent until it merges into a smaller circular profile. A wave guide section721with a substantially constant radius transverse to the signal propagation section extends from a larger reception cone to the low-band ports720,722.

The first transition section718extends from the reception end714to the low-band ports720,722. The first low-band port720lies in the “X-Z” plane and leads to a first low-band wave guide724for communicating a first linear polarity (e.g., horizontal or “H” polarity) of the low-band signal. The second low-band port722lies in the “Y-Z” plane and leads to a second low-band wave guide726for communicating a second linear polarity (e.g., vertical or “V” polarity) of the low-band signal. The first low-band wave guide724includes a high-band rejection filter734to prevent the high-band signal from propagating through the low-band wave guide724, and the second low-band wave guide726includes a high-band rejection filter736to prevent the high-band signal from propagating through the low-band wave guide726. As the first transition section718is located between the reception end714and the low-band ports720,722(i.e., above the low-band ports), both the high-band and low-band signals propagate through the first transition section718.

The horn712further includes a second transition section730that extends from below the low-band ports720,722to the high-band port716. As the second transition section730is located between the low-band ports720,722and the high-band port716, (i.e., below the low-band ports), only the high-band signal propagate through the second transition section730. In this particular embodiment, the transition section721includes a pair of ridges740(only one ridge is illustrated inFIG. 7Afor clarity, while both ridges are illustrated inFIG. 7D) that impart 90 degrees of differentially phase shift to the linear components of the circular polarity high-band signal to polarize the high-band signal as it propagates through the antenna710. It should be noted here that a specific structure for the high-band port716is not illustrated and is typically implemented in a structure immediately following the high-band port716, such as a high-band wave guide, low-noise amplifier, or other suitable structure. Any type of suitable high-band pickups may be used, such as probes, wave guide openings, a wave guide divided by a septum, and so forth.

FIG. 7Bis a conceptual “X-Y” plane top view of the antenna710illustrating the locations and orientations of the high-band and low-band ports. The first low-band output port720is aligned in the “X” direction and the second low-band output port722is aligned in the “Y” direction. The decreasing circular shape of the reception section719does not affect the polarity of the linear polarity low-band signal. The high-band output ports740,742, on the other hand, are aligned at 45 degrees to the “Y” and “X” axes, respectively. As a result, any ridges in the internal profile of the antenna that are aligned with the “X” axis or the “Y” axis do not affect the polarity of the linearly polarity low-band signal, while they differentially phase shift the linear components of the circular polarity high-band signal as the signal propagates through the antenna. The length, shape and taper of the ridges are therefore specifically designed to impart 90 degrees of differential phase shift to the linear components of the circular polarity high-band signal to polarize the high-band signal as it propagates through the antenna710.

FIG. 7Cis a conceptual “X-Y” plane top view of the multi-band antenna710illustrating the location of section lines A-A and B-B.FIG. 7Dis an “X-Z” plane cross-section side view illustrating internal features of the transition section721as viewed along section line A-A andFIG. 7Cis a “Y-Z” plane cross-section side view further illustrating the internal features of the transition section721as viewed along section line B-B. In this particular embodiment, the ridges740lie in the “X-Z” plane and are aligned in the “X” direction. The size, shape and locations of the ridges are specifically designed to impart the desired 90 differential phase shift to the linear components of the circular polarity high-band signal to polarize the high-band signal as it propagates through the upper wave guide section721.

As a specific example, the high-band signal can in the frequency range of 18.3-20.2 GHz and the low-band signal can be in the in the frequency range of 10.7-12.75 GHz. At these frequencies when designed to illuminate a substantially oblong reflector the approximate dimensions will be as follows:

Total Feed length=75 mm

High Band Circular WG with Ridge section L=28 mm, Diameter=10 mm

Low Band Rectangular Waveguide Port openings=19 mm×9.5 mm, with center displaced 60 mm from center line of feed. The antennas shown in the sets of figures corresponding to a single embodiment (i.e., the set of figures consisting ofFIGS. 1A-1H, the set of figures consisting ofFIGS. 2A-2H, etc.) are shown generally to scale within the drawing set with the expanded section drawings shown approximately 2:1 with respect to the main illustration. However, the antennas are not shown strictly to scale between drawing sets and the precise dimensions of each embodiment vary in accordance with the specific engineering. The precise dimensions of each embodiment may also vary in practice based on the type and size of reflector used, the type and location of the amplifier used, whether dielectrics are located in the wave guide, and other design considerations. Therefore, the specific dimensions stated above are representative for a typical DVBS embodiment but by no way exclusive.

It should be further understood that in practice, for example in DVBS systems, the high-band signal defines a large number of information carrying frequency channels within the high-band frequency range, and the low-band signal similarly defines a large number of frequency channels within the low-band frequency range. In addition, each polarity provides a separate set of information carrying channels for each frequency channel. Moreover, with digital information encoding, each polarity of each frequency channel can carry multiple distinct digital programming channels. As a result, the multi-band antennas described above actually carry hundreds, and potentially over a thousand, distinct digital programming channels within the high-band and low-band signals simultaneously communicated by the antenna.

In addition, several methods of introducing the needed phase differential between orthogonal linear components can be used in the opposite slop phase differential section described for embodiment 2 including but not limited to using sections of elliptical, rectangular or oblong waveguides, septums, irises, ridges, screws, dielectrics in circular, square, elliptical rectangular, or oblong waveguides. In addition the needed phase differential could be achieved by picking up or splitting off the orthogonal components via probes as in an LNBF or slots as in an OMT (or other means) and then delaying (via simple length or well establish phase shifting methods) one component the appropriate amount relative to the other component in order to achieve the nominal desired total 90° phase differential before recombining.

Elliptically shaped horn apertures are described in the examples in this disclosure, however this invention can be applied to any device that introduces phase differentials between orthogonal linear components that needs to be compensated for in order to achieve good CP conversion and cross polarization (Cross polarization) isolation including but not limited to any non-circular beam feed, rectangular feeds, oblong feeds, contoured corrugated feeds, feed radomes, specific reflector optics, reflector radomes, frequency selective surfaces etc.