The present invention relates generally to communication systems and more specifically to concurrent bidirectional communication of signals within the same frequency band.
An antenna array is a group of multiple connected antennas coupled to a common source or load to act as a single antenna and produce a directive radiation pattern. Usually, the spatial relationship of the individual antennas also contributes to the directivity of the antenna array. A phased array antenna is an array of antennas in which the relative phases or time delays of the signals feeding the antennas are varied in a manner that the effective radiation pattern of the entire array is reinforced in a desired direction and suppressed in undesired directions.
An Electronically Scanned Array (ESA) is a type of phased array antenna, in which transceivers include a large number of solid-state transmit/receive modules. In ESAs, an electromagnetic beam is emitted by broadcasting radio frequency energy that interferes constructively at certain angles in front of the antenna. An active electronically scanned array (AESA) is a type of phased array antenna whose transmitter and receiver (transceiver) functions are composed of numerous small solid-state transmit/receive modules (TRMs) or components. AESA antennas aim their beam by emitting separate radio waves from each module that interfere constructively at certain angles in front of the antenna.
Typically, the basic building block of a conventional AESA is the Transmit/Receive module or TR module, which can be packaged to form an AESA antenna element, and may include a radiator, receiver Low Noise Amplifier (LNA), transmit Power Amplifier (PA), and digitally controlled phase or delay and gain components. Several of these TR modules are placed on antenna panels in a grid format for transmitting and receiving communication signals. Digital control of the transmit/receive gain and phase allows an AESA antenna to steer or point the resultant antenna beam without physically moving the antenna panel. Typical modern day low cost communications AESA antenna panels employ printed circuit radiators connected to surface mount Monolithic Microwave Integrated Circuit (MMIC) devices that contain the LNA, PA and phase/gain control circuitry, all on a single printed circuit board (PCB).
The ability to transmit and receive from the same AESA antenna panel is typically governed by the operational scenario of the antenna, and provides satisfactory performance for half-duplex operation (i.e., separate time slots for transmit and receive), or with significant operational frequency separation between the transmitter and the receiver. For full-duplex operation and simultaneous transmission and reception of signals within the same frequency band, individual antenna panels for transmitting and for receiving are typically utilized and physically separated by some distance to avoid co-site interference (signals from the transmit antenna coupling into the receive antenna and interfering with the reception of the desired signal).
Additionally, a single AESA antenna panel has practical limitations in scan angle in both azimuth and elevation in its ability to steer or form a beam. Beam shape and signal strength both degrade as the beam is steered away from an antenna panel normal vector (or boresight) to the scan angle edges, typically by +/−60 degrees from normal. Therefore, supporting communications in any direction around a circle with the radio platform at the center requires either the AESA antenna panel to physically move or rotate, or multiple AESA antenna panels spaced about the circle to provide 360 degrees of coverage. Rotating the antenna panel is a satisfactory solution in the single link scenario where there is only one direction in which the antenna must point. It does however become unacceptable for the multi-link cases where multiple simultaneous links can be established in any direction from the radio platform.
A further desirable and beneficial feature of the AESA antenna panel is that it can be designed to support multiple simultaneous beams or communication links from a single panel. This is realized by integrating multiple separate channel paths within the MMIC devices connected to the same printed circuit radiators.
In the case of a hub station, relay station or tower configuration (either a mobile hub or a stationary hub servicing mobile users), the antenna array must support multiple communication links arriving at any direction around the circle with the station in the center. This antenna array can be formed with multiple AESA antenna panels capable of each supporting multiple beams or links. While three antenna panels or “faces” of the antenna array can be used with +/−60 degrees of scan (120 degrees each face) to cover the entire 360 degree circle, four faces provide some overlap between coverage zones to allow for link handover from one antenna to the adjacent antenna as the platforms move relative to one another.
However, this conventional antenna array configuration is bulky and inflexible. In many applications, including aircrafts, an airborne antenna subsystem is needed to support multiple simultaneous transmit and receive beams in a compact aerodynamic mechanical configuration. This requires being able to place the transmit and receive AESA antenna panels as close as possible together within the same antenna array assembly.
In some embodiments, the disclosed embodiments are directed to a compact AESA antenna array providing multi-beam simultaneous transmit and receive operation with hemispherical coverage and co-site interference mitigation through placement of transmit and receive antenna panels relative to each other in the same assembly.
In some embodiments, the disclosed invention is an active electronically scanned array (AESA) antenna configuration for simultaneous transmission and receiving of communication signals. The antenna configuration includes: a housing having eight sides; a first transmit AESA panel including transmit electronic circuitry mounted on a first side of the housing; a first receive AESA panel including receive electronic circuitry mounted on a second side of the housing adjacent to the first transmit AESA panel and forming an angle of about 45 degrees with the first transmit AESA panel; a second transmit AESA panel including transmit electronic circuitry mounted on a third side of the housing adjacent to the first receive AESA panel and forming an angle of about 45 degrees with the first receive AESA panel; a second receive AESA panel including receive electronic circuitry mounted on a fourth side of the housing adjacent to the second AESA transmit panel and forming an angle of about 45 degrees with the second AESA transmit panel; a third transmit AESA panel including transmit electronic circuitry mounted on a fifth side of the housing adjacent to the second AESA receive panel and forming an angle of about 45 degrees with the second AESA receive panel; a third receive AESA panel including receive electronic circuitry mounted on a sixth side of the housing adjacent to the third transmit AESA panel and forming an angle of about 45 degrees with the third AESA transmit panel; a fourth transmit AESA panel including transmit electronic circuitry mounted on a seventh side of the housing adjacent to the third receive AESA panel and forming an angle of about 45 degrees with the third receive AESA panel; and a fourth receive AESA panel including receive electronic circuitry mounted on an eight side of the housing adjacent to the fourth transmit AESA panel and the first transmit AESA panel, and forming an angle of about 45 degrees with fourth transmit AESA panel and the first transmit AESA panel at a respective side thereof, where each of the transmit and receive AESA panels are tilted by a cant angle with respect to a vertical axis of the antenna configuration.
In some embodiments, the disclosed invention is an active electronically scanned array (AESA) antenna configuration for simultaneous transmission and receiving of communication signals. The antenna configuration includes: a housing having six sides; a first transmit AESA panel including transmit electronic circuitry mounted on a first side of the housing; a first receive AESA panel including receive electronic circuitry mounted on a second side of the housing adjacent to the first transmit AESA panel and forming an angle of about 60 degrees with the first transmit AESA panel; a second transmit AESA panel including transmit electronic circuitry mounted on a third side of the housing adjacent to the first receive AESA panel and forming an angle of about 60 degrees with the first receive AESA panel; a second receive AESA panel including receive electronic circuitry mounted on a fourth side of the housing adjacent to the second transmit AESA panel and forming an angle of about 60 degrees with the second transmit AESA panel; a third transmit AESA panel including transmit electronic circuitry mounted on a fifth side of the housing adjacent to the second receive AESA panel and forming an angle of about 60 degrees with the second receive AESA panel; and a third receive AESA panel including receive electronic circuitry mounted on a sixth side of the housing adjacent to the third transmit AESA panel and forming an angle of about 60 degrees with the third transmit AESA panel and the first transmit panel at a respective side thereof, wherein each of the transmit and receive AESA panels are tilted by a cant angle with respect to a vertical axis of the antenna configuration.
The cant angle may be in a range of 0 to 45 degrees to form a cone-shaped housing having a tapered cross section from the top to the bottom in the vertical direction.
These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings.
In some embodiments, the disclosed invention is a compact physical arrangement of both communication transmit and receive antenna panels simultaneously operating in the same frequency band and providing multi-beam, hemispherical coverage and co-site interference mitigation. In some embodiments, the antenna panel assembly comprises an octagonal (or hexagonal) cone array housing which provides four (or three) panels of (for example, Ku-Band) transmit panels including related transmit electronic circuitry and four (or three) panels of (for example, Ku-Band) receive panels including related receive electronic circuitry, where the transmit and receive panels alternate in their placement and therefore no transmit panel is adjacent to another transmit panel and no receive panel is adjacent to another receive panel on a different face of the housing. Each receive panel is offset from its adjacent transmit panel by about 45 degrees in the case of octagonal or 60 degrees in the case of hexagonal array (plus-minus the manufacturing calibration or offset errors) to form the generally octagonal (or hexagonal) cone shape and reduce co-site interferences.
Each of the eight (or six) faces (sides) of the configuration is canted by the same angle (for example, 0-45 degrees) from a vertical axis of the assembly from its top to its bottom to provide full hemispherical coverage for the platform to which the antenna panel assembly is mounted. This way, the cross sections of the octagonal cone array housing in planes perpendicular to the vertical axis, are tapered from top (depicted in
The eight sides of the cone assembly alternate between transmit and receive antenna panels. The alternating transmit and receive antenna panels are offset by 45 degrees from each other and canted from the vertical axis provide a compact multi-beam antenna configuration which mitigate co-site interference and provide full hemispherical coverage. An AESA antenna array assembly design allows full hemispherical coverage using an array of individual AESA T/R antenna panels, each designed for maximum 60 degree scan angle from the normal line, by adding more panels and thus expanding the field of view to 360 degrees. In some embodiments, the size of the assembly is scalable based on operating frequency, number of beams required and scan capabilities of the individual antenna panels. For example, for higher frequency signals, the size of the individual AESA antenna panels may be reduced since the size of the panels is based on the spacing of the individual elements which is inversely proportional to the operating frequency. If the size of the AESA antenna panels that comprise the array assembly are reduced, then the overall size of the antenna array can be reduced accordingly.
Although two transmit AESA panels 206 and one receive AESA panel 208 are shown on each transmit and receive face, respectively, one skilled in the art would recognize that the embodiments are not limited to this configuration and may have more or less than two AESA panels on each face. For example, each of the transmit and receive faces 202a-202h may have a plurality of transmit or receive AESA panels for simultaneous transmission or receiving of a plurality of communication signals. In some embodiments, the eight face panels 202a-202h are secured in the housing 201 by a frame 212, which is compact, sturdy and light-weight. In some embodiments, the panel and/or the housing is comprised of light material, such as Aluminum, polymer, carbon fiber, or any other structurally sound material or combination thereof.
Electronic circuitry, printed circuit board (PCB) and other peripheral components 210 of the AESA antenna array assembly 200 are accommodated inside of the housing 201, however, can be located elsewhere within the installation platform. In some embodiments, each of the transmit AESA panels 206 and receive AESA panels 208 are sized based on the desired operating frequency and scan angle/beam shape of the system, and can be combined in any desired configuration as long as the transmit and receive panels are configured on separate faces/sides and the AESA panels are offset by 45 degrees from one another.
Similar to the embodiments in
Electronic circuitry, printed circuit board (PCB) and other peripheral components of the AESA antenna array assembly may be accommodated inside of the housing 614, however, can be located elsewhere within the installation platform. In some embodiments, each of the transmit AESA panels and receive AESA panels are sized based on the desired operating frequency and scan angle/beam shape, and can be combined in any desired configuration as long as the transmit and receive AESA panels are mounted on separate sides (in the case of a housing on a face panel) and the AESA panels are offset by about 60 degrees.
As shown in
It will be recognized by those skilled in the art that various modifications may be made to the illustrated and other embodiments of the invention described above, without departing from the broad inventive scope thereof. It will be understood therefore that the invention is not limited to the particular embodiments or arrangements disclosed, but is rather intended to cover any changes, adaptations or modifications which are within the scope and spirit of the invention as defined by the appended claims.
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Number | Date | Country | |
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20200227826 A1 | Jul 2020 | US |