Patent Grant
9537212
1. Field of the Invention
This present invention relates generally to microwave devices, and more particularly, to antenna arrays.
2. Related Art
In today's modern society satellite communication systems have become common place. There are now numerous types of communication satellites in various orbits around the Earth transmitting and receiving huge amounts of information. Telecommunication satellites are utilized for microwave radio relay and mobile applications, such as, for example, communications to ships, vehicles, airplanes, personal mobile terminals, Internet data communication, television, and radio broadcasting. As a further example, with regard to Internet data communications, there is also a growing demand for in-flight Wi-Fi® Internet connectivity on transcontinental and domestic flights. Unfortunately, because of these applications, there is an ever increasing need for the utilization of more communication satellites and the increase of bandwidth capacity of each of these communication satellites.
An obvious problem to solving this need is that individual communication satellite systems are very expensive to fabricate, place in Earth orbit, and operate and maintain. Another problem to solving this need is that there are limiting design factors to increasing the bandwidth capacity in a new communication satellite. One of these limiting design factors is the relative compact physical size and weight of a communication satellite. Communication satellite designs are limited by the size and weight parameters that are capable of being loaded into and delivered into orbit by a modern satellite delivery system (i.e., the rocket system). The size and weight limitations of the communication satellite limit the type of electrical, electronic, power generation, and mechanical subsystems that may be included in the communication satellite. As a result, the limit of these types of subsystems are also limiting factors to increasing the bandwidth capacity of the satellite communication.
It is appreciated by those skilled in the art, that in general, the limiting factors to increased bandwidth capacity of the communication satellite are determined by the transponders, antenna system(s), and processing system(s) of the communication satellite.
With regard to the antenna system (or systems), most communication satellite antenna systems include some type of antenna array system. In the past reflector antennas (such as parabolic dishes) were utilized with varying numbers of feed array elements (such as feed horns). Unfortunately, typically these reflector antenna systems scanned their antenna beams utilizing mechanical means instead of electronic means. These mechanical means generally include relatively large, bulky, and heavy mechanisms (i.e., antenna gimbals).
More recently, there have been satellites that have been designed utilizing non-reflector phased array antenna systems. These phased array antenna systems are capable of increasing the bandwidth capacity of the antenna system as compared to previous reflector type of antenna systems. Additionally, these phased array antenna systems are capable of directing and steering antenna beams sometimes without mechanically moving the phase array antenna system. Generally, dynamic phased array antenna systems utilize variable phase shifters to move the antenna beam without physically moving the phased array antenna system. Fixed phased array antenna systems, on the other hand, utilize fixed phased shifters to produce an antenna beam that is stationary with respect to the face of the phased array antenna system. A such, fixed phased array antenna systems require the movement of the entire antenna system (with for example, an antenna gimbal) to directing and steering the antenna beam.
Unfortunately, while dynamic phased array antenna systems are more desirable then fixed phased array antenna systems they are also more complex and expensive since they require specialized active components (such as power amplifiers and active phase shifters) and control systems. As such, there is a need for a new type of phased array antenna system capable of electronically scanning an antenna beam that is robust, efficient, compact, and solves the previously described problems.
An antenna array system for directing and steering an antenna beam is described in accordance with the present invention. In an example of an implementation, the antenna array system may include a feed waveguide having a feed waveguide length, at least two directional couplers in signal communication with the feed waveguide, at least two pairs of planar coupling slots along the feed waveguide length, and at least two horn antennas. The feed waveguide may have a feed waveguide wall, at least one turn along the feed waveguide length, a first feed waveguide input at a first end of the feed waveguide, and a second feed waveguide input at a second end of the feed waveguide. The feed waveguide is configured to receive a first input signal at the first feed waveguide input and a second input signal at the second feed waveguide input.
Each directional coupler, of the at least two directional couplers, has a bottom wall that is adjacent to the waveguide wall of the feed waveguide and each directional coupler is configured to produce a first coupled signal from the first input signal and a second coupled signal from the second input signal. A first pair of planar coupling slots, of the at least two pairs of planar coupling slots, corresponds to the a first directional coupler, of the at least two directional couplers, and a second pair of planar coupling slots, of the at least two pairs of planar coupling slots, corresponds to the a second directional coupler, of the at least two directional couplers. Additionally, the first pair of planar coupling slots are cut into the feed waveguide wall of the feed waveguide and the adjacent bottom wall of the first directional coupler and the second pair of planar coupling slots are cut into the feed waveguide wall of the feed waveguide and the adjacent bottom wall of the second directional coupler.
A first horn antenna, of the at least two horn antennas, is in signal communication with the first directional coupler and a second horn antenna, of the at least two horn antennas, is in signal communication with the second directional coupler. The first horn antenna is configured to receive both the first coupled signal and the second coupled signal from the first directional coupler and the second horn antenna is configured to receive both the first coupled signal and the second coupled signal from the second directional coupler. Additionally, the first horn antenna is configured to produce a first polarized signal from the received first coupled signal and a second polarized signal from the received second coupled signal and the second horn antenna is configured to produce a first polarized signal from the received first coupled signal and a second polarized signal from the received second coupled signal, where the first polarized signal of the first horn antenna is cross polarized with the second polarized signal of the first horn antenna and the first polarized signal of the second horn antenna is cross polarized with the second polarized signal of the second horn antenna. Furthermore, the first polarized signal of the first horn antenna is polarized in the same direction as the first polarized signal of the second horn antenna and the second polarized signal of the first horn antenna is polarized in the same direction as the second polarized signal of the second horn antenna.
In an example of operation, the antenna array system performs a method that includes receiving a first input signal at the first feed waveguide input and a second input signal at the second feed waveguide input, wherein the second input signal is propagating in the opposite direction of the first input signal. Coupling the first input signal to a first directional coupler, of the at least two directional couplers, where the first directional coupler produces a first coupled output signal of the first directional coupler and coupling the first input signal to a second directional coupler, of the at least two directional couplers, where the second directional coupler produces a first coupled output signal of the second directional coupler. The method also includes coupling the second input signal to the second directional coupler, wherein the second directional coupler produces a second coupled output signal of the second directional coupler and coupling the second input signal to the first directional coupler, where the first directional coupler produces a second coupled output signal of the first directional coupler. The method further includes radiating a first polarized signal from a first horn antenna, of the at least two horn antennas, in response to the first horn antenna receiving the first coupled output signal of the first directional coupler and radiating a second polarized signal from the first horn antenna, in response to the first horn antenna receiving the second coupled output signal of the first directional coupler. The method moreover includes radiating a first polarized signal from a second horn antenna, of the at least two horn antennas, in response to the second horn antenna receiving the second coupled output signal of the second directional coupler and radiating a second polarized signal from the second horn antenna, in response to the second horn antenna receiving the second coupled output signal of the second directional coupler.
In another example of an implementation, the antenna array system may include a feed waveguide having a feed waveguide length, at least four directional couplers in signal communication with the feed waveguide, at least four pairs of planar coupling slots along the feed waveguide length, and at least two horn antennas. The feed waveguide may have a feed waveguide wall, at least five turns along the feed waveguide length, a first feed waveguide input at a first end of the feed waveguide, and a second feed waveguide input at a second end of the feed waveguide. The feed waveguide is configured to receive a first input signal at the first feed waveguide input and a second input signal at the second feed waveguide input.
Each directional coupler, of the at least four directional couplers, has a bottom wall that is adjacent to the waveguide wall of the feed waveguide and each directional coupler is configured to produce a coupled signal from either the first input signal or the second input signal. A first pair of planar coupling slots, of the at least four pairs of planar coupling slots, corresponds to the a first directional coupler, of the at least four directional couplers; a second pair of planar coupling slots, of the at least four pairs of planar coupling slots, corresponds to the a second directional coupler, of the at least four directional couplers; a third pair of planar coupling slots, of the at least four pairs of planar coupling slots, corresponds to the a third directional coupler, of the at least four directional couplers; and a fourth pair of planar coupling slots, of the at least four pairs of planar coupling slots, corresponds to the a fourth directional coupler, of the at least four directional couplers. The first pair of planar coupling slots are cut into the feed waveguide wall of the feed waveguide and the adjacent bottom wall of the first directional coupler; the second pair of planar coupling slots are cut into the feed waveguide wall of the feed waveguide and the adjacent bottom wall of the second directional coupler; the third pair of planar coupling slots are cut into the feed waveguide wall of the feed waveguide and the adjacent bottom wall of the third directional coupler; and the fourth pair of planar coupling slots are cut into the feed waveguide wall of the feed waveguide and the adjacent bottom wall of the fourth directional coupler.
A first horn antenna, of the at least two horn antennas, is in signal communication with the first directional coupler and the second directional coupler and a second horn antenna, of the at least two horn antennas, is in signal communication with the third directional coupler and the fourth directional coupler. The first horn antenna is configured to receive the coupled signal from the first directional coupler and the coupled signal from the second directional coupler and the second horn antenna is configured to receive the coupled signal from the third directional coupler and the coupled signal from the fourth directional coupler. Additionally, the first horn antenna is configured to produce a first polarized signal from the received coupled signal from the first directional coupler and a second polarized signal from the received coupled signal from the second directional coupler and the second horn antenna is configured to produce a first polarized signal from the received coupled signal from the third directional coupler and a second polarized signal from the received coupled signal from the fourth directional coupler, where the first polarized signal of the first horn antenna is cross polarized with the second polarized signal of the first horn antenna and the first polarized signal of the second horn antenna is cross polarized with the second polarized signal of the second horn antenna. Moreover, the first polarized signal of the first horn antenna is polarized in the same direction as the first polarized signal of the second horn antenna and second polarized signal of the first horn antenna is polarized in the same direction as the second polarized signal of the second horn antenna.
Other devices, apparatus, systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims.
The invention may be better understood by referring to the following figures. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views.
An antenna array system for directing and steering an antenna beam is described in accordance with the present invention. In an example of an implementation, the antenna array system may include a feed waveguide having a feed waveguide length, at least two directional couplers in signal communication with the feed waveguide, at least two pairs of planar coupling slots along the feed waveguide length, and at least two horn antennas. The feed waveguide may have a feed waveguide wall, at least one turn along the feed waveguide length, a first feed waveguide input at a first end of the feed waveguide, and a second feed waveguide input at a second end of the feed waveguide. The feed waveguide is configured to receive a first input signal at the first feed waveguide input and a second input signal at the second feed waveguide input.
Each directional coupler, of the at least two directional couplers, has a bottom wall that is adjacent to the waveguide wall of the feed waveguide and each directional coupler is configured to produce a first coupled signal from the first input signal and a second coupled signal from the second input signal. A first pair of planar coupling slots, of the at least two pairs of planar coupling slots, corresponds to the a first directional coupler, of the at least two directional couplers, and a second pair of planar coupling slots, of the at least two pairs of planar coupling slots, corresponds to the a second directional coupler, of the at least two directional couplers. Additionally, the first pair of planar coupling slots are cut into the feed waveguide wall of the feed waveguide and the adjacent bottom wall of the first directional coupler and the second pair of planar coupling slots are cut into the feed waveguide wall of the feed waveguide and the adjacent bottom wall of the second directional coupler.
A first horn antenna, of the at least two horn antennas, is in signal communication with the first directional coupler and a second horn antenna, of the at least two horn antennas, is in signal communication with the second directional coupler. The first horn antenna is configured to receive both the first coupled signal and the second coupled signal from the first directional coupler and the second horn antenna is configured to receive both the first coupled signal and the second coupled signal from the second directional coupler. Additionally, the first horn antenna is configured to produce a first polarized signal from the received first coupled signal and a second circularly signal from the received second coupled signal and the second horn antenna is configured to produce a first polarized signal from the received first coupled signal and a second polarized signal from the received second coupled signal, where the first polarized signal of the first horn antenna is cross polarized with the second polarized signal of the first horn antenna and the first polarized signal of the second horn antenna is cross polarized with the second polarized signal of the second horn antenna. Furthermore, the first polarized signal of the first horn antenna is polarized in the same direction as the first polarized signal of the second horn antenna and second polarized signal of the first horn antenna is polarized in the same direction as the second polarized signal of the second horn antenna.
The polarizations of the first polarized signals and second polarized signals of the first horn antenna and second horn antenna, respectively, may be any desired polarization scheme including linear polarization, circular polarization, elliptical polarization, etc. As an example, the first polarized signal and the second polarized signal of the first horn antenna may be a first linearly polarized signal and second linearly polarized signal where the first linearly polarized signal and second linearly polarized signal are cross polarized (i.e., the polarizations are orthogonal) because one may be “vertical” polarized and the other may be “horizontal” polarized. Similarly, the first polarized signal and second polarized signal of the first horn antenna may be a first linearly polarized signal and the second linearly polarized signal where the first linearly polarized signal and second linearly polarized signal are cross polarized. Additionally, in this example, the first linearly polarized signal of the first horn antenna and the first linearly polarized signal of the second horn antenna may be polarized in the same direction (i.e., both may be vertical polarized or both may be horizontally polarized). Similarly, the second linearly polarized signal of the first horn antenna and the second linearly polarized signal of the second horn antenna may be polarized in the same direction.
In the case of circular polarization, the first polarized signal and the second polarized signal of the first horn antenna may be a first circularly polarized signal and the second circularly polarized signal of the first horn where the first circularly polarized signal and second circularly polarized signal are cross polarized because the first circularly polarized signal of the first horn antenna rotates in the opposite direction of the second circularly polarized signal of the first horn antenna (i.e., one may be right-hand circularly polarized and the other may be left-hand circularly polarized). Similarly, the first polarized signal and the second polarized signal of the second horn antenna may be a first circularly polarized signal and the second circularly polarized signal of the second horn antenna where the first circularly polarized signal and second circularly polarized signal are cross polarized because the first circularly polarized signal of the second horn antenna rotates in the opposite direction of the second circularly polarized signal of the second horn antenna.
Additionally, in this example, the first circularly polarized signal of the first horn antenna and the first circularly polarized signal of the second horn antenna may be polarized in the same direction (i.e., both may rotate in the same direction such that both may be right-hand circularly polarized (“RHCP”) or both may be left-hand circularly polarized (“LHCP”)). Similarly, the second circularly polarized signal of the first horn antenna and the second circularly polarized signal of the second horn antenna may be polarized in the same direction.
In an example of operation, the antenna array system performs a method that includes receiving a first input signal at the first feed waveguide input and a second input signal at the second feed waveguide input, wherein the second input signal is propagating in the opposite direction of the first input signal. Coupling the first input signal to a first directional coupler, of the at least two directional couplers, where the first directional coupler produces a first coupled output signal of the first directional coupler and coupling the first input signal to a second directional coupler, of the at least two directional couplers, where the second directional coupler produces a first coupled output signal of the second directional coupler. The method also includes coupling the second input signal to the second directional coupler, wherein the second directional coupler produces a second coupled output signal of the second directional coupler and coupling the second input signal to the first directional coupler, where the first directional coupler produces a second coupled output signal of the first directional coupler. The method further includes radiating a first circularly polarized signal from a first horn antenna, of the at least two horn antennas, in response to the first horn antenna receiving the first coupled output signal of the first directional coupler and radiating a second circularly polarized signal from the first horn antenna, in response to the first horn antenna receiving the second coupled output signal of the first directional coupler. The method moreover includes radiating a first circularly polarized signal from a second horn antenna, of the at least two horn antennas, in response to the second horn antenna receiving the second coupled output signal of the second directional coupler and radiating a second circularly polarized signal from the second horn antenna, in response to the second horn antenna receiving the second coupled output signal of the second directional coupler.
In another example of an implementation, the antenna array system may include a feed waveguide having a feed waveguide length, at least four directional couplers in signal communication with the feed waveguide, at least four pairs of planar coupling slots along the feed waveguide length, and at least two horn antennas. The feed waveguide may have a feed waveguide wall, at least five turns along the feed waveguide length, a first feed waveguide input at a first end of the feed waveguide, and a second feed waveguide input at a second end of the feed waveguide. The feed waveguide is configured to receive a first input signal at the first feed waveguide input and a second input signal at the second feed waveguide input.
Each directional coupler, of the at least four directional couplers, has a bottom wall that is adjacent to the waveguide wall of the feed waveguide and each directional coupler is configured to produce a coupled signal from either the first input signal or the second input signal. A first pair of planar coupling slots, of the at least four pairs of planar coupling slots, corresponds to the a first directional coupler, of the at least four directional couplers; a second pair of planar coupling slots, of the at least four pairs of planar coupling slots, corresponds to the a second directional coupler, of the at least four directional couplers; a third pair of planar coupling slots, of the at least four pairs of planar coupling slots, corresponds to the a third directional coupler, of the at least four directional couplers; and a fourth pair of planar coupling slots, of the at least four pairs of planar coupling slots, corresponds to the a fourth directional coupler, of the at least four directional couplers. The first pair of planar coupling slots are cut into the feed waveguide wall of the feed waveguide and the adjacent bottom wall of the first directional coupler; the second pair of planar coupling slots are cut into the feed waveguide wall of the feed waveguide and the adjacent bottom wall of the second directional coupler; the third pair of planar coupling slots are cut into the feed waveguide wall of the feed waveguide and the adjacent bottom wall of the third directional coupler; and the fourth pair of planar coupling slots are cut into the feed waveguide wall of the feed waveguide and the adjacent bottom wall of the fourth directional coupler.
A first horn antenna, of the at least two horn antennas, is in signal communication with the first directional coupler and the second directional coupler and a second horn antenna, of the at least two horn antennas, is in signal communication with the third directional coupler and the fourth directional coupler. The first horn antenna is configured to receive the coupled signal from the first directional coupler and the coupled signal from the second directional coupler and the second horn antenna is configured to receive the coupled signal from the third directional coupler and the coupled signal from the fourth directional coupler. Additionally, the first horn antenna is configured to produce a first polarized signal from the received coupled signal from the first directional coupler and a second polarized signal from the received coupled signal from the second directional coupler and the second horn antenna is configured to produce a first polarized signal from the received coupled signal from the third directional coupler and a second polarized signal from the received coupled signal from the fourth directional coupler. The first polarized signal of the first horn antenna is cross polarized with the opposite direction of the second polarized signal of the first horn antenna and the first polarized signal of the second horn antenna is cross polarized with the opposite direction of the second polarized signal of the second horn antenna. Moreover, the first polarized signal of the first horn antenna is polarized in the same direction as the first polarized signal of the second horn antenna and the second polarized signal of the first horn antenna is polarized in the same direction as the second polarized signal of the second horn antenna.
Turning to
In
In
The bent waveguide structure of the directional coupler 150 is known as an “E-bend” because it distorts the electric field, unlike the bends (i.e., turns) 124, 126, 128, 130, and 132 in the feed waveguide 102 that are known as “H-bends” because they distort the magnetic field. Generally, an E-bend waveguide may be constructed utilizing a gradual bend or by utilizing a number of step transitions (as shown in
The reason for utilizing a bent waveguide structure for the directional coupler 150 is to allow the horn antenna 114 to radiate in a normal (i.e., perpendicular) direction away from the X-Y (134 and 136) plane that defines physical layout structure of the feed waveguide 102. It is appreciated that the directional coupler 150 may also be non-bent if the horn antenna 150 is designed to radiate in a direction parallel to the X-Y (134 and 136) plane that defines physical layout structure of the feed waveguide 102.
It is appreciated that while only one combination of directional coupler 150, horn antenna 114, power amplifiers 162 and 164, and feed waveguide 102 turn 128 is shown, this combination is also representative of the other directional couplers 140, 142, 144, 146, 148, and 150, plurality of power amplifiers 152, 154, 156, 158, 160, 162, and 164, horn antennas 104, 106, 108, 110, 112, and 114, and feed waveguide 102 turns 124 and 126. It is noted that feed waveguide 102 turns 130 and 132 are not visible in this side view because they are blocked by the second end 122 of the feed waveguide 102.
Turning to
In this example, both the feed waveguide 102 and the directional couplers 140, 142, 144, 146, 148, and 150 are shown to be rectangular waveguides having broad-walls (as seen in
In an example of operation, the feed waveguide 102 acts as traveling wave meandering-line array feeding the plurality of directional couplers 140, 142, 144, 146, 148, and 150. The antenna array system 100 receives a first input signal 184 and a second input signal 186. Both the first input signal 184 and second input signal 186 may be TE10, or TE01, mode propagated signals. The first input signal 184 is input into the first feed waveguide input 116 at the first end 118 of the feed waveguide 102 and the second input signal 186 is input into the second feed waveguide input 120 at the second end 122 of the feed waveguide 102. In this example, both the first input signal 184 and second input signal 186 propagate along the direction of the X 134 coordinate axis into opposite ends of the feed waveguide 102.
Once in the feed waveguide 102, the first input signal 184 and second input signal 186 propagate along the feed waveguide 102 in opposite directions coupling parts of their respective energies into the different directional couplers. Since the first input signal 184 and second input signal 186 are traveling wave signals that are travelling in opposite directions along a length 188 of the feed waveguide 102, they will have a phase delay of about 180 degrees relative to each other at any given point within the feed waveguide 102. In general, the waveguide length 188 of the feed waveguide 102 is several wavelengths long (of the operating wavelength of the first input signal 184 and second input signal 186) so as to be long enough to create a length (not shown) between the pairs of planar coupling slots (not shown) that is also multiple wavelengths of the operating wavelengths of the first input signal 184 and second input signal 186. The reason for this length between pairs of planar coupling slots (not shown) is to create a phase increment needed for beam steering the antenna beam (not shown) of the antenna array system 100 as a function of frequency. As an example, the length between the pairs of planar coupling slots may be between 5 to 7 wavelengths long.
In this example, as the first input signal 184 travels from the first end 118 to the second end 122 of the feed waveguide 102, the first input signal 184 successively couples a portion of its energy to each direction coupler 140, 142, 144, 146, 148, and 150 until the a first remaining signal 190 of the remaining energy (if any) is outputted from the second end 122 of the feed waveguide 102. Similarly, as the second input signal 186 travels in the opposite direction from the second end 122 to the first end 118 of the feed waveguide 102, the second input signal 186 successively couples a portion of its energy to each direction coupler 140, 142, 144, 146, 148, and 150 until a second remaining signal 192 of the remaining energy (if any) of the second input signal 186 is outputted from the first end 118 of the feed waveguide 102. It is appreciated that by optimizing the design of the directional couplers 140, 142, 144, 146, 148, and 150, the first remaining signal 190 and second remaining signal 192 both may be reduced to close to zero.
In this example, when the first input signal 184 travels along the feed waveguide 102, it will couple a first portion of it energy to the directional coupler 140, which will pass this first coupled output signal to the horn antenna 104. The remaining portion of the first input signal 184 will then travel along the feed waveguide 102 to the directional coupler 142 where it will couple another portion of it energy to the directional coupler 142, which will pass this second coupled output signal to the second horn antenna 106. This process will continue such that another portion of the first input signal 184 will be coupled to directional couplers 144, 146, 148, and 150 and passed to horn antennas 108, 110, 112, and 114, respectively. The remaining portion of the first input signal 184 will then be output from the second end 122 of the feed waveguide 102 as the first remaining signal 190. Similarly, when the second input signal 186 travels along the feed waveguide 102, it will couple a first portion of it energy to the directional coupler 150, which will pass this first coupled output signal to the horn antenna 114. The remaining portion of second input signal 186 will then travel along the feed waveguide 102 to the directional coupler 148 where it will couple another portion of it energy to the directional coupler 148, which will pass this second coupled output signal to the second horn antenna 112. This process will continue such that another portion of the second input signal 186 will be coupled to directional couplers 146, 144, 142, and 140 and passed to horn antennas 110, 108, 106, and 104, respectively. The remaining portion of the second input signal 186 will then be output from the first end 118 of the feed waveguide 102 as the second remaining signal 192.
As a result, the first input signal 184 and second input signal 196 will cause the excitation of horn antennas 104, 106, 108, 110, 112, and 114. The horn antennas 104, 106, 108, 110, 112, and 114 may be configured to produce RHCP and LHCP signals when excited by the coupled portions of the first input signal 184 and second input signal 186, respectively. Alternatively, the horn antennas 104, 106, 108, 110, 112, and 114 may be configured to produce horizontal polarization and vertical polarization signals when excited by the coupled portions of the first input signal 184 and second input signal 186, respectively.
It is appreciated that a first circulator, or other isolation device, (not shown) may be connected to the first end 118 to isolate the first input signal 184 from the outputted second remaining signal 192 and a second circulator, or other isolation device, (not shown) may be connected to the second end 122 to isolate the second input signal 186 from the outputted first remaining signal 190. It is appreciated by those skilled in the art that the amount of coupled energy from the feed waveguide 102 to the respective directional couplers 140, 142, 144, 146, 148, and 150 is determined by predetermined design choices that will yield the desired radiation antenna pattern of the antenna array system 100.
It is appreciated by those skilled in the art that the circuits, components, modules, and/or devices of, or associated with, the antenna array system 100 are described as being in signal communication with each other, where signal communication refers to any type of communication and/or connection between the circuits, components, modules, and/or devices that allows a circuit, component, module, and/or device to pass and/or receive signals and/or information from another circuit, component, module, and/or device. The communication and/or connection may be along any signal path between the circuits, components, modules, and/or devices that allows signals and/or information to pass from one circuit, component, module, and/or device to another and includes wireless or wired signal paths. The signal paths may be physical, such as, for example, conductive wires, electromagnetic wave guides, cables, attached and/or electromagnetic or mechanically coupled terminals, semi-conductive or dielectric materials or devices, or other similar physical connections or couplings. Additionally, signal paths may be non-physical such as free-space (in the case of electromagnetic propagation) or information paths through digital components where communication information is passed from one circuit, component, module, and/or device to another in varying digital formats without passing through a direct electromagnetic connection.
Turning to
In an example of operation, when the first input signal 344 and second input signals 346 are injected (i.e., inputted) into the feed waveguide 300 they excite both magnetic and electric fields within the feed waveguide 300. This gives rise to induced currents in the walls (i.e., the broad-wall 302 and narrow wall (not shown)) of feed waveguide 300 that are at right angles to the magnetic field. As an example, in
It is noted that in
Turning back to
It is appreciated by those skilled in the art that
Turning to
In an example of operation, a first signal 628 (corresponding to the first input signal) is propagating along the feed waveguide 600. When the first signal 628 reaches the pair of planar coupling slots 602 and 604, most of the power will continue to propagate along the feed waveguide 600 as shown by remaining first input signal 630; however, a small part of the first signal 628 will be coupled from the feed waveguide 600 to the directional coupler 606 via the pair of planar coupling slots 602 and 604. This coupled energy is shown as forward coupled signal 632. The forward coupled signal 632 is then passed to the first power amplifier 616, which amplifies the amplitude of the signal and passes the amplified first coupled signal 634 to an input feed of a horn antenna (not shown).
Similarly, a second signal 636 (corresponding to the second input signal) is propagating along the feed waveguide 600 in the opposite direction of the first signal 628. When the second signal 636 reaches the pair of planar coupling slots 602 and 604, most of the power will continue to propagate along the feed waveguide 600 as shown by remaining second input signal 638; however, a small part of the second signal 636 will be coupled from the feed waveguide 600 to the directional coupler 606 via the pair of planar coupling slots 602 and 604. This coupled energy is shown as reverse coupled signal 640. The reverse coupled signal 640 is then passed to the second power amplifier 618, which amplifies the amplitude of the signal and passes the amplified second coupled signal 642 to another input feed of the horn antenna. The horn antenna may then utilize the amplified first coupled signal 634 to produce and radiate a RHCP signal and the amplified second coupled signal 642 to produce and radiate a LHCP signal. Alternatively, the horn antenna may then utilize the amplified first coupled signal 634 to produce and radiate a horizontal polarized signal and the amplified second coupled signal 642 to produce and radiate a vertical polarized signal.
In this example, the pair of planar coupling slots 602 and 604 are spaced 644 apart by approximately a quarter-wavelength. The reason for a quarter-wavelength spacing is well known in the art for directional couplers but may be generally stated as causing the first signal 628 to couple energy from the feed waveguide 600 to the directional coupler 6096 in one direction while causing the second signal 636 to couple energy from the feed waveguide 600 to the directional coupler 606 in the opposite direction. The reason for this is that in general coupled signal propagate in both directions, however, the phase delay caused by the planar coupling slots 602 and 604 will cause one of the coupled signals to cancel in one direction while adding phases in another. Specifically, when the first signal 628 reaches the first planar coupling slot 602, part of the energy (i.e., a coupled signal) from the first signal 628 will couple into the directional coupler 606 via the first planar coupling slot 602. When the remaining first signal reaches the second planar coupling slot 604, another part of the energy from the remaining first signal will couple into the directional coupler 606 via the second planar coupling slot 604. Since these two coupled signals are propagating in the same direction (i.e., towards the first power amplifier 616), they are in-phase and constructively add in phase to produce the forward coupled signal 632. However, any energy coupled in the opposite direction (i.e., towards the second power amplifier 618) will constructively cancel out because the coupled signal (produced by the first planar coupling slot 602) from the first signal 628 traveling towards the second power amplifier 618 will lead the coupled signal (produced by the second planar coupling slot 604) from the remaining first signal by approximately 180 degrees in phase. This results because, taking the first planar coupling slot 602 as a reference, the coupled signal going to the second planar coupling slot 604 has to travel a further quarter-wavelength in the feed waveguide 600, and then quarter-wavelength back again in the directional coupler 606. Hence the two coupled signals in the direction of the second power amplifier 618 cancel each other. It is appreciated that in practice a small amount of power (i.e., energy) will reach the second power amplifier 618 because of the imperfections in designing the directional coupler 606. However, this may be minimized by proper design techniques that are known to those skilled in the art. It is appreciated that the same coupling process is applicable to the second signal 636 such that the reverse coupled signal 640 is result of constructive addition, while a coupled signals from the second signal 636 in the direction of the first power amplifier 616 is cancelled.
In
In this example, the horn antenna 700 includes a first horn input 704 and a second horn input 706 at the feed input 708 of the horn antenna 700. In this example, the horn antenna 700 includes a septum polarizer 710. It is appreciated by those skilled in the art that a septum polarizer 710 is a waveguide device that is configured to transform a linearly polarized signal at the first horn input 704 and second horn input 706 into a circularly polarized signal at the output 712 of the waveguide into the horn antenna aperture 714. The horn antenna 700 then radiates a circularly polarized signal 716 into free space.
In an example of operation, linear signals feed into the first horn input 704 may be transformed into RHCP signals at the output 712 of the waveguide, while linear signals feed into the second horn input 706 may be transformed into LHCP signals at the output 712 of the waveguide. The RHCP or LHCP signals may then be transmitted as the circularly polarized signal 716 into free space.
Alternatively, a different horn antenna design may be utilized that produces linear polarization signals, instead of circularly polarized signals, from the linear signals feed into the first horn input (not shown) and the second horn input (not shown). Vertical and horizontal polarized signals, instead of RHCP and LHCP signals, may then be transmitted into free space. In this example an orthomode transducer (“OMT”) may be utilized at each element rather than a septum polarizer.
In
Turning to
The feed waveguide 902 includes a first feed waveguide input 964 at a first end 966 of the feed waveguide 902 and a second feed waveguide input 968 at a second end 970 of the feed waveguide 902, where the second end 970 is at the opposite end of the feed waveguide 902 with respect to the first end 966. The feed waveguide 902 may be a serpentine or meandering waveguide that includes a plurality of turns (i.e., bends) 972, 974, 976, 978, 980, 982, and 984. In this example, the physical layout of the feed waveguide 902 may be described by three-dimensional Cartesian coordinates with coordinate axes X 985, Y 986, and Z 987, where the feed waveguide 902 is located in a plane defined by the X 985 and Y 986 coordinate axes. Additionally, the plurality of horn antennas 928, 930, 932, 934, 936, and 938 are also shown extending in the plane defined by the X 985 and Y 986 coordinate axes.
Again, it is appreciated by those skilled in the art, that while only six horn antennas 928, 930, 932, 934, 936, and 938 and seven visible turns 972, 974, 976, 978, 980, 982, and 984, and six none visible turns in the feed waveguide 902 are shown, this is for illustration purposes only and antenna array system 900 may include any even number of directional couplers, horn antennas, and power amplifiers with a corresponding number of turns needed to feed the directional couplers. As another example, the antenna array system 900 may include 120 directional couplers and 60 horn antennas, and 121 turns in the feed waveguide. It is again appreciated that the number of horn antennas determines the numbers directional couplers, and turns in the feed waveguide. Again, each horn antenna of the plurality of horn antennas 928, 930, 932, 934, 936, and 938 act as an individual radiating element of the antenna array system 900. In operation, each horn antenna's individual radiation pattern typically varies in amplitude and phase from each other horn antenna's radiation pattern. The amplitude of the radiation pattern for each horn antenna is controlled by a power amplifier that controls the amplitude of the excitation current of the horn antenna. Similarly, the phase of the radiation pattern of each horn antenna is determined by the corresponding delayed phase caused by the feed waveguide 902 in feeding the directional couplers that correspond to the horn antenna.
In
In an example of operation, when a first input signal 988 in injected into the first feed waveguide input 964, the first input signal 988 will travel along the feed waveguide 902 and couple a first portion of its energy to the forward directional coupler 904, which will pass this first coupled output signal to the horn antenna 928 via the power amplifier 940. The remaining portion of the first input signal will then travel along the feed waveguide 902 to the reverse directional coupler 916 where it will not couple any energy because the reverse direction coupler 916 is designed to only couple signals that are traveling in the opposite direction. As such, the remaining portion of the first input signal will continue to travel along the feed waveguide 902 to the forward directional coupler 906 and couple a second portion of its energy to the forward directional coupler 906, which will pass this second coupled output signal to the horn antenna 930 via the power amplifier 944. The remaining portion of the first input signal will then travel along the feed waveguide 902 to the reverse directional coupler 918 where it will not couple any energy because the reverse direction coupler 918 is designed to only couple signals that are traveling in the opposite direction. As such, the remaining portion of the first input signal will continue to travel along the feed waveguide 902 to the forward directional coupler 908 and couple a third portion of its energy to the forward directional coupler 908, which will pass this third coupled output signal to the horn antenna 932 via the power amplifier 948. The remaining portion of the first input signal will then travel along the feed waveguide 902 to the reverse directional coupler 920 where it will not couple any energy because the reverse direction coupler 920 is designed to only couple signals that are traveling in the opposite direction. As such, the remaining portion of the first input signal will continue to travel along the feed waveguide 902 to the forward directional coupler 910 and couple a fourth portion of its energy to the forward directional coupler 910, which will pass this fourth coupled output signal to the horn antenna 934 via the power amplifier 952. The remaining portion of the first input signal will then travel along the feed waveguide 902 to the reverse directional coupler 922 where it will not couple any energy because the reverse direction coupler 922 is designed to only couple signals that are traveling in the opposite direction. As such, the remaining portion of the first input signal will continue to travel along the feed waveguide 902 to the forward directional coupler 912 and couple a fifth portion of its energy to the forward directional coupler 912, which will pass this fifth coupled output signal to the horn antenna 936 via the power amplifier 956. The remaining portion of the first input signal will then travel along the feed waveguide 902 to the reverse directional coupler 924 where it will not couple any energy because the reverse direction coupler 924 is designed to only couple signals that are traveling in the opposite direction. As such, the remaining portion of the first input signal will continue to travel along the feed waveguide 902 to the forward directional coupler 914 and couple a sixth portion of its energy to the forward directional coupler 914, which will pass this sixth coupled output signal to the horn antenna 938 via the power amplifier 960. The remaining portion of the first input signal will then travel along the feed waveguide 902 to the reverse directional coupler 926 where it will not couple any energy because the reverse direction coupler 926 is designed to only couple signals that are traveling in the opposite direction. As such, the remaining portion of the first input signal will continue to travel along the feed waveguide 902 and output, as the first remaining signal 990, via the second feed waveguide input 968. It is appreciated that by optimizing the design of forward directional couplers 904, 906, 908, 910, 912, and 914, the first remaining signal 990 may be reduced to close to zero.
Similarly, when a second input signal 992 is in injected into the second feed waveguide input 968, the second input signal 992 will travel along the feed waveguide 902 (in the opposite direction of the first input signal 988) and couple a first portion of its energy to the reverse directional coupler 926, which will pass this first coupled output signal to the horn antenna 938 via the power amplifier 962. The remaining portion of the second input signal will then travel along the feed waveguide 902 to the forward directional coupler 914 where it will not couple any energy because the forward direction coupler 914 is designed to only couple signals that are traveling in the opposite direction (i.e., the direction of the first input signal 988). As such, the remaining portion of the second input signal will continue to travel along the feed waveguide 902 to the reverse directional coupler 924 and couple a second portion of its energy to the reverse directional coupler 924, which will pass this second coupled output signal to the horn antenna 936 via the power amplifier 958. The remaining portion of the second input signal will then travel along the feed waveguide 902 to the forward directional coupler 912 where it will not couple any energy because the forward directional coupler 912 is designed to only couple signals that are traveling in the opposite direction. As such, the remaining portion of the second input signal will continue to travel along the feed waveguide 902 to the reverse directional coupler 922 and couple a third portion of its energy to the reverse directional coupler 922, which will pass this third coupled output signal to the horn antenna 934 via the power amplifier 954. The remaining portion of the second input signal will then travel along the feed waveguide 902 to the forward directional coupler 910 where it will not couple any energy because the forward directional coupler 910 is designed to only couple signals that are traveling in the opposite direction. As such, the remaining portion of the second input signal will continue to travel along the feed waveguide 902 to the reverse directional coupler 920 and couple a fourth portion of its energy to the reverse directional coupler 920, which will pass this fourth coupled output signal to the horn antenna 932 via the power amplifier 950. The remaining portion of the second input signal will then travel along the feed waveguide 902 to the forward directional coupler 908 where it will not couple any energy because the forward directional coupler 908 is designed to only couple signals that are traveling in the opposite direction. As such, the remaining portion of the second input signal will continue to travel along the feed waveguide 902 to the reverse directional coupler 918 and couple a fifth portion of its energy to the reverse directional coupler 918, which will pass this fifth coupled output signal to the horn antenna 936 via the power amplifier 946. The remaining portion of the second input signal will then travel along the feed waveguide 902 to the forward directional coupler 906 where it will not couple any energy because the forward directional coupler 906 is designed to only couple signals that are traveling in the opposite direction. As such, the remaining portion of the second input signal will continue to travel along the feed waveguide 902 to the reverse directional coupler 916 and couple a sixth portion of its energy to the reverse directional coupler 916, which will pass this sixth coupled output signal to the horn antenna 928 via the power amplifier 942. The remaining portion of the second input signal will then travel along the feed waveguide 902 to the forward directional coupler 904 where it will not couple any energy because the forward directional coupler 904 is designed to only couple signals that are traveling in the opposite direction. As such, the remaining portion of the second input signal will continue to travel along the feed waveguide 902 and output, as the second remaining signal 992, via the first feed waveguide input 964. Again, it is appreciated that by optimizing the design of reverse directional couplers 916, 918, 920, 922, 924, and 926, the second remaining signal 994 may be reduced to close to zero.
Again, it is appreciated that a first circulator, or other isolation device, (not shown) may be connected to the first end 966 to isolate the first input signal 988 from the outputted second remaining signal 994 and a second circulator, or other isolation device, (not shown) may be connected to the second end 970 to isolate the second input signal 992 from the outputted first remaining signal 990. It is also appreciated by those skilled in the art that the amount of coupled energy from the feed waveguide 902 to the respective directional couplers 904, 906, 908, 910, 912, 914, 916, 918, 920, 922, 924, and 926 is determined by predetermined design choices that will yield the desired radiation antenna pattern of the antenna array system 900.
Turning to
The difference between the first implementation of the antenna array system 100 shown in
In the first implementation, each directional coupler 140, 142, 144, 146, 148, and 150 is designed to couple signals from both the first input signal 184 and second input signal 186 irrespective of the direction of travel. Both coupled signals are passed to the respective horn antenna 104, 106, 108, 110, 112, and 114 via different feeds paths from the directional coupler to the horn antenna.
It is appreciated that the meandering waveguide shown in
As an example of operation, both the first and second implementations of the antenna array system may be utilized as standalone antenna systems (i.e., direct radiation system) or as part of a reflector antenna system. Turing to
In
It will be understood that various aspects or details of the invention may be changed without departing from the scope of the invention. It is not exhaustive and does not limit the claimed inventions to the precise form disclosed. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpose of limitation. Modifications and variations are possible in light of the above description or may be acquired from practicing the invention. The claims and their equivalents define the scope of the invention.
It will be understood that various aspects or details of the invention may be changed without departing from the scope of the invention. It is not exhaustive and does not limit the claimed inventions to the precise form disclosed. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpose of limitation. Modifications and variations are possible in light of the above description or may be acquired from practicing the invention. The claims and their equivalents define the scope of the invention.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3473162 | Veith | Oct 1969 | A |
| 4348680 | Collier | Sep 1982 | A |
| 4864308 | Raab | Sep 1989 | A |
| 7286093 | Artis | Oct 2007 | B2 |
| 7289077 | Artis | Oct 2007 | B2 |
| Entry |
|---|
| European Patent Office Communication re European Search Report, Application No. 15152493.1. |
| Number | Date | Country | |
|---|---|---|---|
| 20150236414 A1 | Aug 2015 | US |
