Patent Grant
7737904
Not applicable.
The present invention generally relates to antenna systems and, in particular, relates to antenna systems for multiple frequency bands.
The current technology for commercial satellites is capable of providing either local-channel direct broadcast satellite (DBS) services at 12/17 GHz bands or Ka-band broadband satellite services at 20/30 GHz bands. This is mainly due to bandwidth limitations of antenna systems that could provide efficient radiation over a bandwidth ratio of about 1.64 (ratio of the highest frequency to lowest frequency, e.g., 30/18.3=1.64) or less. Thus, it has been difficult to produce very wideband antennas, with bandwidth ratios beyond 1.64, using conventional techniques. Two separate sets of antennas can be carried out to overcome the above problem, but the two sets of antennas (one for DBS and the other for broadband) can not be accommodated on the spacecraft due to the reason that each set of antennas requires the use of four large reflector antennas (about 100 inch in aperture each) and the required eight large reflector antennas can not be accommodated on the spacecraft. Because of these bandwidth and aperture limitations of the antennas, operators like DirecTV had to launch two separate satellites, one supporting local-channel DBS services (e.g., DTV-4S, DTV-10, DTV-11, Echo 10) and the other for Ka-band broadband satellite services (e.g., SpaceWay, Anik-F2, EutelSat-Ka, Viasat).
In accordance with an exemplary embodiment of the present invention, a novel quad-band antenna provides efficient radiation patterns over more than an octave bandwidth with a bandwidth ratio of more than 2.44. Such a quad-band antenna can support both forward DBS (12/17 GHz bands) and the Ka-band broadband satellite services using a single set of antennas (e.g., a single set of four reflector antennas). In another embodiment, it can support the recent reverse DBS (17/25 GHz bands) and the Ka-band broadband satellite services using one set of antennas (e.g., one set of four reflector antennas).
In one aspect of the present invention, an antenna system is disclosed for transmitting and/or receiving radio frequency signals in multiple frequency bands. The antenna system comprises a horn antenna and a feed network. The horn antenna is configured to transmit and/or receive radio frequency signals in multiple frequency bands that are spread over more than an octave bandwidth with at least a 2.44-to-1 bandwidth ratio. The horn antenna comprises a throat, an aperture, and an interior surface. The throat is disposed at a first end of the horn antenna. The aperture is disposed distantly from the throat at a second end of the horn antenna. The interior surface is disposed in the horn antenna between the first end and the second end of the horn antenna. The interior surface comprises a plurality of slope discontinuities.
The feed network is coupled to the horn antenna. The feed network comprises a first waveguide section, a first junction, one or more first filters, and a first step-down waveguide section. The first waveguide section is configured to provide a matching network. The first waveguide section is also configured to transmit and/or receive the radio frequency signals in the multiple frequency bands. The first junction is configured to transmit and/or receive the radio frequency signals in first selected one or more frequency bands of the multiple frequency bands and not all of the multiple frequency bands. The one or more first filters is configured to pass the radio frequency signals in the first selected one or more frequency bands of the multiple frequency bands and configured to reject the radio frequency signals in frequency bands not in the first selected one or more frequency bands of the multiple frequency bands.
The first step-down waveguide section is coupled to the first waveguide section. The first step-down waveguide section is also configured to transmit and/or receive the radio frequency signals in second selected one or more frequency bands of the multiple frequency bands and configured to reject the radio frequency signals in the first selected one or more frequency bands of the multiple frequency bands.
In another aspect of the present invention, an antenna system is disclosed for transmitting and/or receiving radio frequency signals in multiple frequency bands. The antenna system comprises a horn antenna and a feed network. The horn antenna is configured to transmit and/or receive radio frequency signals in multiple frequency bands. The horn antenna comprises a throat, an aperture, and an interior surface. The throat is disposed at a first end of the horn antenna. The aperture is disposed distantly from the throat at a second end of the horn antenna. The interior surface is disposed in the horn antenna between the first end and the second end of the horn antenna.
The interior surface comprises a plurality of slope discontinuities. The interior surface increases in diameter from the first end of the horn antenna to the second end of the horn antenna. The interior surface has the smallest diameter at the throat. The interior surface has the largest diameter at the aperture. The diameter of the interior surface at the aperture is less than 12 times the wavelength of the highest frequency of the multiple frequency bands, and the diameter of the interior surface at the aperture is greater than 1.7 times the wavelength of the lowest frequency of the multiple frequency bands.
The feed network is coupled to the horn antenna. The feed network comprises a first waveguide section, a first junction, one or more first filters, and a first step-down waveguide section. The first waveguide section is configured to provide a matching network. The first waveguide section is configured to transmit and/or receive the radio frequency signals in the multiple frequency bands. The first junction is configured to transmit and/or receive the radio frequency signals in first selected one or more frequency bands of the multiple frequency bands and not all of the multiple frequency bands.
The one or more first filters is configured to pass the radio frequency signals in the first selected one or more frequency bands of the multiple frequency bands and is configured to reject the radio frequency signals in frequency bands not within the first selected one or more frequency bands of the multiple frequency bands. The first step-down waveguide section is configured to transmit and/or receive the radio frequency signals in second selected one or more frequency bands of the multiple frequency bands and not in the first selected one or more frequency bands of the multiple frequency bands.
In the following description, reference is made to the accompanying attachment that forms a part thereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and changes may be made without departing from the scope of the present invention.
The invention both to its organization and manner of operation, may be further understood by reference to the drawings that include
The following description of illustrative non-limiting embodiments of the invention discloses specific configurations and components. However, the embodiments are merely examples of the present invention, and thus, the specific features described below are merely used to describe such embodiments to provide an overall understanding of the present invention. One skilled in the art readily recognizes that the present invention is not limited to the specific embodiments described below. Furthermore, certain descriptions of various configurations and components of the present invention that are known to one skilled in the art are omitted for the sake of clarity and brevity. Further, while the term “embodiment” may be used to describe certain aspects of the invention, the term “embodiment” should not be construed to mean that those aspects discussed apply merely to that embodiment, but that all aspects or some aspects of the disclosed invention may apply to all embodiments, or some embodiments. Like components are labeled with identical element numbers for ease of understanding.
In accordance with various exemplary embodiments, the subject technology can overcome the bandwidth and spacecraft accommodation limitations of the current antenna systems. Utilizing multi-band antennas, such as the disclosed “quad-band” antennas, allows for minimal asset allocation on the space segment with improved system cost as well as potential use for common user terminal equipment on the ground. Common ground terminal supporting multiple satellite services reduces the ground segment cost significantly which is often subsidized by the satellite operators as an enticement to consumers to subscribe the services. This common ground terminal would allow for one installation and alignment to a single spacecraft minimizing the installation costs. These could be employed for direct broadcast satellite (DBS) and Ka-band broadband satellite services allowing for two of the three legs of the traditional telecom “triple play” or utilizing voice-over-Internet-protocol (VoIP), allowing for all three legs of the “triple play.” This capability could be utilized for combined standards DBS, or reverse DBS, and Ka-band broadband allowing for use of common antenna assets supporting all of the three services both on the spacecraft and on the ground. An extension of this technology may also be applicable to mobile user terminals for both commercial and government applications.
In one exemplary embodiment, a novel multi-band horn antenna (e.g., a quad-band horn antenna) can support the four distinct frequency bands required to support the local-channel DBS and the broadband satellite services over a bandwidth ratio of 2.44. A multi-band horn antenna of the subject technology can minimize the number of reflectors (e.g., four reflectors instead of eight). This allows an antennas system to stow the deployed reflectors within a 4-meter launch-fairing envelope. The four discrete frequency bands are: (1) 12.2 to 12.7 GHz (“12 GHz frequency band”) for forward DBS downlink, (2) 17.3 to 17.8 GHz (“17 GHz frequency band”) for forward DBS uplink, (3) 18.3 to 20.2 GHz (“20 GHz frequency band”) for broadband downlink, and (4) 28.1 to 30.0 GHz (“30 GHz frequency band”) for broadband uplink. For reverse DBS services, the four discrete frequency bands are: (1) 17.3 to 17.8 GHz (“17 GHz frequency band”) for reverse DBS downlink, (2) 24.75 to 25.25 GHz (“25 GHz frequency band”) for reverse DBS uplink, (3) 18.3 to 20.2 GHz (“20 GHz frequency band”) for broadband downlink, and (4) 28.1 to 30.0 GHz (“30 GHz frequency band”) for broadband uplink.
In the example provided above, the frequency bands are discrete (e.g., distinct) in that each frequency band has its own frequency range, and one frequency band is typically separated from the next frequency band. In other words, a gap may exist between one frequency band and the next frequency band so that the frequency bands are not continuous from one band to the next. It should be noted that the invention is not limited to the exemplary frequency bands described above, and the invention may be utilized for other frequency bands and any number of frequency bands (e.g., two or more).
According to one aspect of the invention, the extreme bandwidth ratio requirement of 2.44 (30 GHz/12.2 GHz) can be met by using a multi-band (e.g., quad-band) smooth-walled multi-mode horn antenna that realizes the high efficiency values required to achieve desired radiation patterns at each of the multiple frequency bands. A feed assembly may be realized using two symmetrical ortho-mode transducer (OMT) junctions (or simply referred later as symmetrical junctions), two diplexers, a number of band-reject filters, and a polarizer resulting in an 8-port feed network that carries all of the multiple discrete frequency bands with proper isolation among the frequency bands and with low axial ratio.
A quad-band horn antenna utilizing the subject technology has achieved high efficiency values of the order 74% to 82% over more than an octave band. A number of feed assemblies have been employed to illuminate each of the reflectors in order to provide about 40 spot beams that carry the DBS (forward or reverse bands) and broadband signals for direct-to-home broadcast of local TV channels as well as Ka-band broadband signals for internet and data applications. While three or four reflectors have been utilized in exemplary embodiments, the invention is not limited to these numbers, and any number of reflectors may be used. The feed array is de-focused from the focal-plane of the reflector in order to optimize the radiation patterns over all the multiple frequency bands. The computed spot beam patterns show that efficient radiation is achieved over all the five frequency bands (including reverse DBS band). This allows the same antenna to be used for forward DBS plus broadband services or reverse DBS plus broadband service applications.
The feed network 380 may include a common waveguide section 332 configured to provide matching network to all the radio frequency signals in multiple frequency bands. The feed network 380 may include a number of network blocks. Three network blocks 301, 302, 303 are shown in this example. Each network block may be configured to transmit and/or receive radio frequency signals in one or two of the multiple frequency bands.
The network block 301 includes a symmetrical junction 304a having multiple waveguide slots (e.g., 4 slots) coupled to the common waveguide section 332. The symmetrical junction 304a may be configured to transmit and/or receive radio frequency signals in first selected one or two frequency bands of the multiple frequency bands and not all of the multiple frequency bands. Multiple filters 306a coupled to the symmetrical junction 304a may be configured to pass the radio frequency signals in the first selected one or two frequency bands of the multiple frequency bands and configured to reject the radio frequency signals in frequency bands not within the first selected one or more frequency bands of the multiple frequency bands. In this example, the first selected one or more frequency bands may be a 12 GHz frequency band, and the network block 301 may be used to transmit radio frequency signals in the 12 GHz frequency band. The arrows shown indicate an exemplary flow of signals for transmission of the 12 GHz band RF signals.
The network block 301 may also include horizontal plane sections 308a and vertical plane section 312a for propagating radio frequency signals. A horizontal plane block 314a may include (i) horizontal plane waveguide bend sections, each of which may be coupled to its respective filter 306a, and (ii) a horizontal plane T-junction coupled to the horizontal plane waveguide bend sections and configured to divide radio frequency signals into horizontal plane radio frequency signals for transmission and to combine horizontal plane radio frequency signals into radio frequency signals for reception.
A vertical plane block 316a may include (i) vertical plane waveguide bend sections, each of which may be coupled to its respective filter 306a, and (ii) a vertical plane T-junction coupled to the vertical plane waveguide bend sections and configured to divide radio frequency signals into vertical plane radio frequency signals for transmission and to combine vertical plane radio frequency signals into radio frequency signals for reception.
A hybrid coupler/polarizer 318a may be configured to combine or divide radio frequency signals and to polarize radio frequency signals from one form to another form (e.g., converting linearly polarized signals to circularly polarized signals and vice versa). The hybrid coupler/polarizer 318a is coupled to a left-hand circular polarization (LCP) port 322a and a right-hand circular polarization (RCP) port 324a at the 12 GHz band of this exemplary drawing.
Still referring to
The network module 302 may further include a polarizer (e.g., a septum polarizer) and a transition section 338 coupled to the second step-down waveguide section 336. The polarizer of block 338 may be configured to polarize signals from one form to another form, like the polarizer of the block 318a described above. The transition section of block 338 may be configured to provide one of the polarized signal to an LCP (left-hand circular polarization) port 342, and the other polarized signal to an RCP (right-hand circular polarization) port 344.
The network module 303 may include components similar to those in the network module 301, and the similar components can perform the same or similar functions. A symmetrical junction 304b is similar to the symmetrical junction 304a, filters 306b are similar to filters 306a, horizontal plane sections 308b are similar to horizontal plane sections 308a, and vertical plane sections 312b are similar to vertical plane sections 312a. A horizontal plane block 314b may be similar to the horizontal plane block 314a. A vertical plane block 316b may be similar to the vertical plane block 316a. A hybrid coupler/polarizer 318b is similar to the hybrid coupler/polarizer 318a.
The network module 303 may include components different from the network module 301. For example, the network module 303 may include multiplexers 352 (e.g., diplexers) coupled to the hybrid coupler and polarizer 318a. The multiplexers 352 (e.g., diplexers) can be used to isolate two or more frequency bands from one another and provide multiple ports for RF signals associated with multiple frequency bands.
In this particular example shown in
In accordance with one exemplary embodiment, the antenna system 300 may be configured to transmit and/or receive radio frequency signals in four frequency bands and utilize eight ports (322a, 324a, 342, 344, 324b, 324c, 322b, and 322c). In particular, the antenna system 300 may be configured to transmit radio frequency signals in the 12 GHz and 20 GHz frequency bands and receive radio frequency signals in the 17 GHz and 30 GHz frequency bands. The horn antenna 230 may also be configured to transmit radio frequency signals in the 12 GHz and 20 GHz frequency bands and receive radio frequency signals in the 17 GHz and 30 GHz frequency bands. The arrows shown in
The network module 302 may be configured to reject radio frequency signals in the 12 GHz frequency band (by the first step-down waveguide section 334) and the reject the 17 and 20 GHz frequency bands (by the second step-down waveguide section 336) so that only the radio frequency signals in the 30 GHz frequency band are sent to the LCP port 342 and RCP port 344.
In the network module 303, the filters 306b may be configured to reject radio frequency signals in the 30 GHz frequency band. The symmetrical junction 304b may be configured to receive radio frequency signals in the 17 GHz frequency band from the first step-down waveguide section 334, and configured to transmit radio frequency signals in the 20 GHz frequency band to the first step-down waveguide section 334.
In this example, the network module 301 handles the lowest frequency band, the network module 302 handles the highest frequency band, and the network module 303 handles two medium frequency bands (between the highest and the lowest frequency bands) that are close together.
As for the eight ports shown in
As shown in
In
The symmetrical junction 304a is symmetrical and may include four waveguide slots 307a (two for the vertical plane and two for the horizontal plane). The two waveguide slots 307a for the vertical plane are located at opposite ends of a circular body of the symmetrical junction 304a (one on top and one on the bottom), and the two waveguide slots 307a for the horizontal plane are located at opposite ends of the body (one on the left and one on the right). The four slots located 90 degrees apart along the circumference of the circular waveguide create a symmetrical structure. The waveguide slots 307a are configured to be resonant at its selected frequency band(s) (e.g., 12 GHz frequency band). The four filters 306a may be configured to reject radio frequency signals in the other frequency bands (e.g., 17, 20 and 30 GHz frequency bands) as well as other frequencies such as radio-astronomy bands and military bands for proper operation of the satellite. It should be noted that the horizontal and vertical plane sections 308a and 312a shown in
For transmission of signals, a coupler/polarizer (such as 318b, which includes a 3-dB hybrid coupler) is configured to phase shift a signal by 90° (e.g., HP and VP signals 612 and 614 are equal in amplitude and 90° out of phase). A coupler/polarizer (such as 318b) is also configured to place a half of the power from the LCP signal 624 onto the VP signal 614, the other half of the power from the LCP signal 624 onto the HP signal 612, a half of the power from the RCP signal 622 onto the VP signal 614, the other half of the power from the RCP signal 622 onto the HP signal 612. If a coupler/polarizer is utilized for reception of signals, a coupler/polarizer (such as 318b) can combine and polarize the HP and VP signals 612 and 614 into the RCP and LCP signals 622 and 624.
The symmetrical junction 304b is symmetrical and may include four waveguide slots 307b (two for the vertical plane and two for the horizontal plane). The two waveguide slots 307b for the vertical plane are located at opposite ends of a circular body of the symmetrical junction 304b (one on top and one on the bottom), and the two waveguide slots 307b for the horizontal plane are located at opposite ends of the body (one on the left and one on the right). The locations of the waveguide slots are symmetrical. The waveguide slots 307b may be configured to be resonant at the selected frequency band(s) (e.g., 17 and 20 GHz frequency bands). The four filters 306b may be configured to reject radio frequency signals in the non-selected frequency bands (e.g., higher frequency bands such as the 30 GHz frequency band). It should be noted that the horizontal and vertical plane sections 308b and 312b shown in
A repeater 790 includes a receiver block 791a (e.g., for the 17 GHz frequency band) configured to downcovert the radio frequency signals received, channel filters 792a configured to selectively pass signals in a selected frequency band(s) (e.g., 12 GHz frequency band) and reject other frequency bands, linearized traveling wave tube amplifiers (LTWTAs) 793a configured to operate, for example, at 12 GHz and to amplify the signals, and output filters 794a configured to selectively pass signals in a selected frequency band(s) (e.g., 12 GHz frequency band) and reject other frequency bands.
Components with like names can perform the same or substantially similar functions. For example, a symmetrical junctions 804a (e.g., passing 17 and 20 GHz frequency bands) and 804c (e.g., passing 25 GHz frequency band) are similar to symmetrical junctions 304a and 304b. A common waveguide section 832 (e.g., passing all of 17, 30, 25 and 30 GHz frequency bands) is similar to the common waveguide section 332.
Filters 806a (e.g., passing 17 and 20 GHz frequency bands and rejecting 25 and 30 GHz frequency bands) and 806c (e.g., passing 25 GHz frequency band and rejecting 30 GHz frequency band) of
Step-down waveguide sections 834 (e.g., passing 25 and 30 GHz frequency bands) and 836 (e.g., passing 30 GHz frequency band) are similar to the step-down waveguide sections 334 and 336. A polarizer & transition section 838 (e.g., passing 30 GHz frequency band) is similar to the polarizer & transition section 338. The multiplexers 852 (e.g., passing 17 and 20 GHz frequency bands) are similar to the multiplexers 352. RCP and LCP ports 824a, 824b, 822a, 822b, 822c, 824c, 842 and 844 are similar to RCP and LCP ports 324a, 324b, 322a, 322b, 322c, 324c, 342 and 344 of
One difference between the like-named components in
The filters 806a may be used to selectively pass radio frequency signals in the lowest frequency bands (e.g., 17 and 20 GHz frequency bands) and reject the other frequency bands (e.g., 25 and 30 GHz). Since 17 and 20 GHz are the close in frequency, these frequency bands are grouped together to be handled using same hardware. The filters 806c may be used to selectively pass radio frequency signals in the 25 GHz frequency band and reject the other high frequency band(s) (e.g., 30 GHz). The RCP port 824b and LCP port 822a may carry transmission signals in the 20 GHz frequency band. The RCP port 824a and LCP port 822b may carry transmission signals in the 17 GHz frequency band. The RCP port 824c and LCP port 822c may carry reception signals in the 25 GHz frequency band. The RCP port 844 and LCP port 842 may carry reception signals in the 30 GHz frequency band.
A hollow area 1050 is substantially funnel-shaped, and is formed within horn antenna 230. The hollow area 1050 extends from the throat 1030 to the aperture 1040 in a gradually tapered fashion along multiple slope discontinuities 2, 3, 4, 5, and 6. In various exemplary embodiments, each of the slope discontinuities 2, 3, 4, 5, and 6 may be located at varying distances from one another. In various exemplary embodiments, there may be any number of slope discontinuities, to include more than five or less than five.
At location 3, the diameter of the interior surface 1020 is about 0.646 inches, and location 3 is about 0.506 inches from location 1. At location 4, the diameter of the interior surface 1020 is about 0.877 inches, and location 4 is about 1.175 inches from location 1. At location 5, the diameter of the interior surface 1020 is about 1.299 inches, and location 5 is about 2.718 inches from location 1. At location 6, the diameter of the interior surface 1020 is about 1.560 inches, and location 6 is about 5.918 inches from location 1. At location 7 (the second end of the horn antenna 230), the diameter of the interior surface 1020 is about 2.1 inches, and location 7 is about 7.901 inches from location 1. Location 7 may be covered by a protective covering (not illustrated) known to not interfere with radio frequency transmission and reception. A protective covering might be utilized to keep debris and unwanted material from entering the hollow area 1050.
While the interior surface 1020 is referred to herein as possessing a “diameter,” those skilled in the art would understand that a horn antenna 230 may have a variety of shapes, and that an aperture 1040 may be circular, elliptical, rectangular, square, polygonal, or some other configuration all within the scope of the present invention. Various exemplary embodiments of the present invention may also have different cross sectional shapes along a longitudinal axis, such as circular, rectangular, elliptical, or the like for either circular or linear polarization.
In certain exemplary embodiments of the present invention, if one were to place an axis 1090 lengthwise along the horn antenna 230 between location 1 (where the throat 1030 is) and location 7 (where the aperture 1040 is), coaxial to the center of the horn antenna 230, it is clear that none of the interior surface 1020 reaches a negative slope with respect to the axis 1090 between location 1 and location 7. In one aspect, the positive slopes of the interior surface 1020 gradually taper from slope discontinuity to slope discontinuity. The interior surface 1020 beyond the throat region (i.e., a region to the right of location 2) comprises linear slopes that are greater than zero and less than ninety degrees in angle with respect to the axis 1090. In one aspect, the interior surface beyond the throat region lacks any surface having a zero degree slope with respect to the axis 1090, and the interior surface beyond the throat lacks any surface having a ninety-degree slope with respect to the axis 1090. Furthermore, in some embodiments, the interior surface 1020 beyond the throat region may lack curved surfaces (e.g., the regions between the slope discontinuities are not curved).
The slopes of the interior surface 1020 may taper gradually without any abrupt changes. For example, in certain exemplary embodiments of the present invention, the slope discontinuities do not include a sharp change such as a ninety-degree angle. In one aspect of certain exemplary embodiments, the slope discontinuities shown in
When tested, the exemplary embodiment of the present invention described in relation to
Horn antennas and systems are also described in the following patent applications: U.S. patent application Ser. No. 12/137,416 entitled “Horn Antenna And System For Transmitting And/Or Receiving Radio Frequency Signals In Multiple Frequency Bands,” filed on Jun. 11, 2008, which is a continuation-in-part of U.S. patent application Ser. No. 11/594,157 entitled “High-Efficiency Horns for an Antenna System,” filed on Nov. 8, 2006, which is a continuation-in-part of U.S. patent application Ser. No. 11/029,390 entitled “Multiple-Beam Antenna System Using High-Efficiency Dual-Band Feed Horns,” filed on Jan. 6, 2005, which claims the benefit of priority under 35 U.S.C. §119 from U.S. Provisional Patent Application Ser. No. 60/622,785 entitled “Multiple-Beam Antenna Using High-Efficiency Dual-Band Horns,” filed on Oct. 29, 2004. U.S. patent application Ser. No. 12/137,416 entitled “Horn Antenna And System For Transmitting And/Or Receiving Radio Frequency Signals In Multiple Frequency Bands,” filed on Jun. 11, 2008 claims the benefit of priority under 35 U.S.C. §119 from U.S. Provisional Patent Application Ser. No. 61/030,507 entitled “Antenna Systems and Methods Supporting Multiple Frequency Bands and Multiple Beams,” filed on Feb. 21, 2008. All of the foregoing applications described in this paragraph are hereby incorporated by reference in their entirety.
For each of
Exemplary embodiments of the present invention include horn antennas configured to obtain high efficiency with higher order transverse electric (TE) modes, for instance, going beyond the dominant TE11 mode to TE12, TE13, TE14, and TE15 etc. modes.
In certain exemplary embodiments of the present invention, the minimum diameter of the aperture 1040 (or the minimum diameter of an interior surface 1040 of a horn antenna 230 of
In certain exemplary embodiments of the present invention, the maximum diameter of an aperture 1040 (or the maximum diameter of an interior surface 1020 of a horn antenna 230 of
For the frequency bands of 12.2 GHz to 30.0 GHz, a minimum diameter may be 1.65 inches, and a maximum diameter may be 4.72 inches according to one embodiment of the present invention.
According to exemplary embodiments, a multi-band (e.g., quad-band) antennas and systems (e.g., a feed assembly) use high efficiency feed. A multi-band antenna has extremely wide bandwidth covering about 12 GHz to 30 GHz that supports conventional DBS, reverse DBS, and Ka-band broadband satellite services. One common antenna can support all three services and can utilize forward or reverse DBS, and broadband services simultaneously. A multi-band antenna has applications for future satellites as well as ground terminals.
According to certain aspects, the disclosed invention for the first time has realized an antenna system providing more than an octave bandwidth while maintaining highly efficient radiation at four distinct frequency bands at a given time, but could support five bands. In one exemplary embodiment, this is achieved by using an efficient multi-band (e.g., quad-band) horn antenna that supports four distinct frequency bands that are widely separated and that combines both DBS and Ka-band broadband satellite services into one common antenna system. The advantages are, for example: (a) a single satellite can provide both services instead of two satellites, (b) the number of reflectors is reduced by a factor of two, (c) the number of horn antennas and feed networks is reduced by a factor of two, (d) the subject technology provides a significant reduction in the ground support equipment in terms of, for example, the number of gateways and the number of user terminals, (e) the subject technology can support both forward DBS and the reverse DBS services using one common antenna system. Furthermore, the operators can now provide conventional DBS/reverse DBS, and Ka-band broadband satellite services to the users using a common ground terminal that provides TV and internet services, and (f) the subject technology has significant impact on commercial as well as military satellites.
It is understood that any specific order or hierarchy or steps in the processes disclosed herein are merely exemplary illustrations and approaches. Based upon design preferences, it is understood that any specific order or hierarchy of steps in the process may be re-arranged. Some of the steps may be performed simultaneously.
The previous description is provided to enable persons of ordinary skill in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the claim language. Headings and subheadings, if any, are used for convenience only and do not limit the invention. All structural and functional equivalents to the elements of the various aspects described throughout the disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the invention. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the above description.
As used herein, a reference to an element in the singular is not intended to mean “one and only one” unless specifically stated, but rather “one or more.” The term “selected” may refer to predetermined or pre-selected. The term “some” refers to one or more. Underlined and/or italicized headings and subheadings are used for convenience only, do not limit the invention, and are not referred to in connection with the interpretation of the description of the invention. All structural and functional equivalents to the elements of the various embodiments of the invention described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and intended to be encompassed by the invention. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the above description.
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