This disclosure generally relates to antenna arrays, and more particularly, to a multi-orientation phased antenna array and associated method.
Electro-magnetic radiation at microwave frequencies has relatively more distinct propagation and/or polarization characteristics than electro-magnetic radiation at lower frequencies. Antenna arrays that transmit and receive electro-magnetic radiation at microwave frequencies, such as (AESAs), may be useful for transmission and/or reception of microwave signals at a desired polarity, scan pattern, and/or look angle. AESAs are typically driven by a signal distribution circuit that generates electrical signals for transmission by the AESA, and may also be used to condition electro-magnetic signals received by the active electronically scanned array.
According to one embodiment, an antenna apparatus includes first and second antenna arrays configured in a support structure. Each antenna array has multiple antenna elements that transmit and/or receive electro-magnetic radiation. The elements of the first antenna array are oriented in a boresight direction that is different from the boresight direction in which the elements of the second antenna array are oriented. A plurality of switches alternatively couples the first antenna elements or the second antenna elements to a signal distribution circuit.
Some embodiments of the disclosure may provide numerous technical advantages. For example, one embodiment of the multi-orientation antenna array may provide up to twice the field-of-view (FOV) relative to other antenna arrays that only generate transmit or receive beam in a single direction. This expanded FOV is provided by two antenna arrays that are mounted together in a configuration such that two independently controlled beams may be generated. This configuration of the two antenna arrays may also enable re-use of certain components for reduced weight, size, and costs relative to other antenna arrays. In certain cases, the antenna apparatus may also forego the need for gimbal and servo mechanisms that may further reduce the cost, weight, and power requirements associated with antenna arrays.
Some embodiments may benefit from some, none, or all of these advantages. Other technical advantages may be readily ascertained by one of ordinary skill in the art.
A more complete understanding of embodiments of the disclosure will be apparent from the detailed description taken in conjunction with the accompanying drawings in which:
It should be understood at the outset that, although example implementations of embodiments are illustrated below, various embodiments may be implemented using any number of techniques, whether currently known or not. The present disclosure should in no way be limited to the example implementations, drawings, and techniques illustrated below. Additionally, the drawings are not necessarily drawn to scale.
First antenna array 12a includes multiple antenna elements 18a that are oriented in a plane perpendicular to direction 16a; and second antenna array 12b includes multiple antenna elements 18b that are oriented in a plane perpendicular to direction 16b. When antenna elements 18a of first antenna array 12a are energized with signals having a similar amplitude and phase, it generates a beam within scan volume 14a. Likewise, when antenna elements 18b of second antenna array 12b are energized with signals having a similar amplitude and phase, it generates a beam within the scan volume 14b. Switches may be implemented to alternatively couple antenna elements 18a or antenna elements 18b to drive circuitry in multi-orientation antenna array 10. Additional details of certain embodiments of switch configurations that may be implemented are described in detail with respect to
In the particular embodiment shown, antenna arrays 12a and 12b operate at frequencies in the range of 8 to 10 Gigahertz (GHz), have an aperture size of approximately 4 feet2, and has a peak transmitting power of approximately 5 Watts peak power per radiating element. Other embodiments may have similar or differing characteristics including lower or higher frequencies, lower or higher peak power per element, and different aperture sizes. In the particular embodiment shown, each antenna array 12a and 12b provides a scan volume 14a and 14b having an azimuthal width W of approximately 120 degrees and an elevational height H of approximately 60 degrees. Thus, the effective scan volume 14a and 14b provided by antenna array 10 may be approximately 240 degrees along the azimuthal extent around antenna array 10. In other embodiments, each antenna array 12a and 12b may have an azimuthal width W greater than 120 degrees or less than 120 degrees. Additionally, each antenna array 12a and 12b may have an elevational height H greater than 60 degrees or less than 60 degrees.
First and second antenna arrays 12a and 12b may have any suitable number and type of antenna elements 18a and 18b. For example, in the particular embodiment shown in
Certain embodiments of antenna array 10 may provide an enhanced field-of-view (FOV) for scan volumes 14a and 14b that may be 180 degrees, or approximately 180 degrees, with respect to one another at a reduced weight and cost relative to known antenna arrays. Antenna array 10 utilizes two sets of antenna elements 18a and 18b housed in a common support structure. In certain embodiments, antenna elements 18a and 18b share common radio frequency (RF), power circuitry, signal circuits, structural plates, and/or cooling structures. This commonality may provide reduced weight and/or cost relative to other antenna arrays.
AESAs may provide inertialess scanning over a FOV that is limited by the element pattern of the individual radiating elements. Antenna arrays having a relatively large FOV have typically been achieved by either mounting the AESAs on a gimbal having a servo mechanism to position the FOV at the desired angle, or by configuring multiple AESAs in a fixed installation. For the particular case in which the desired FOVs of the two scan volumes 14a and 14b are 180 degrees with respect to one another, the invention described herein may provide an antenna array 10 having reduced weight and lower cost relative to the known AESAa in certain embodiments.
Referring to
In the particular embodiment shown, antenna elements 18a′, 18b′, 18a″, and 18b″ comprise slotline radiators. In certain embodiments, antenna elements 18a′, 18b′, 18a″, and 18b″ may be any device that is adapted to radiate electro-magnetic radiation upon excitation at a desired frequency.
Power and control interface 28 may include various components that may include, but are not limited to one or more signal distribution circuits 34.
Referring to FIGS. 1 and 2A-2C, when arranged in multi-orientation antenna array 10, one outer edge 19a of circuit board 24 is aligned along the aperture of first antenna array 12a and its other outer edge 19b is aligned with the aperture of second antenna array 12b. Thus, antenna elements 18a of antenna array 12a and antenna elements 18b of antenna array 12b may be formed on a common printed wiring board 24. Certain embodiments of multi-orientation antenna array 10 may provide advantages over other antenna arrays in that multiple antenna arrays 12a and 12b may leverage reduced parts count of certain components for reduced weight, size, and/or cost relative to other antenna array designs.
Coldplate 26 is thermally coupled to printed wiring board 24 and functions as a cooling system to convey heat away from signal channels 32 during operation of multi-orientation antenna array 10. In the particular embodiment shown, coldplate 26 is formed of a thermally conductive material, such as aluminum. In other embodiments, coldplate may be made of any suitable material and have any shape that conveys heat away from circuit board 24 or power and control interface 28. For example, coldplate 26 may include a fluid that is configured to transfer heat away from components of circuit board 24 by undergoing a phase change in the presence of close thermal coupling with its components. As can be seen, antenna array 12a and antenna array 12b share a common cooling system that further serves to reduce weight, size, and/or costs relative to other antenna array designs.
Each signal channel 32 of modular element assembly 22′ is common to first antenna array 12a and second antenna array 12b. In operation, each signal channel 32 may be alternatively coupled to either an antenna element 18a of first antenna array 12a or an antenna element 18b of second antenna array 12b. That is, first antenna array 12a or second antenna array 12b may be used while the other remains idle. Thus, the beam generated by first antenna array 12a may be steered in one direction, while the beam generated by second antenna array 12b is steered in a another direction independently of the direction in which the beam of first antenna array 12a is steered.
Switches 36 may be actuated to select which of first antenna array 12a or second antenna array 12b is used. Modular element assembly 22′ may provide an advantage in that the quantity of signal channels 32 and/or signal distribution circuits 34 used may be reduced by a factor of 2, thus providing a reduction in the weight, size, and costs relative to other antenna arrays having twice as many signal channels 32 and/or signal distribution circuits 34.
Switches 36′ alternatively couple signal distribution circuit 34 between signal channels 32 of first antenna array 12a, and signal channels 32 of second antenna array 12b. In this configuration, a beam may be generated by first antenna array 12a while the second antenna array 12b is idle. Alternatively, another beam may be generated by the second antenna array 12b while the first antenna array 12a is idle. Embodiments of modular element assembly 22″ may provide an advantage over modular element assembly 22′ of
Each signal distribution circuit 34′ and 34″ functions independently of each other for unique, simultaneous control over their respective antenna elements 18a and 18b. For example, a beam generated by first antenna array 12a may be steered in one direction, while the other beam generated by second antenna array 12b is steered in another direction independently of the direction in which the beam is steered. Time or frequency modulation of the signals may be utilized to provide isolation. Modular element assembly 22′″ may provide performance advantages similar to that of modular element assembly 22″. Additionally, modular element assembly 22′″ may be implemented with a common cooling system and/or support structure in a similar manner to modular element assembly 22′ or modular element assembly 22″.
Each multi-orientation antenna array 10 may have scan volumes 14a, 14b, 14c, and 14d that are approximately 120 degrees wide along their azimuthal extent. Antenna array 10 provides expanded azimuthal coverage relative to the azimuthal coverage provided by multi-orientation antenna array 10. As shown, combined antenna array 100 may provide azimuthal coverage that may be up to, and including a 360 degree azimuthal extent around combined antenna array 100.
Modifications, additions, or omissions may be made to multi-orientation antenna array 10, 100, or 200 without departing from the scope of the invention. The components of multi-orientation antenna array 10, 100, or 200 may be integrated or separated. For example, circuitry comprising signal channels 32 may be provided as circuit modules separately from signal distribution circuit 34, or signal channels 32 may be integrally formed with signal distribution circuit 34. Moreover, the operations of multi-orientation antenna array 10, 100, or 200 may be performed by more, fewer, or other components. For example, each modular element assembly 22 may include other circuitry, such as power circuits or other signal conditioning circuits that conditions electrical signals received by, or transmitted to antenna elements 18a and/or 18b. Additionally, operations of signal distribution circuit 34 may be controlled by any type of controller, such as those using any suitable logic comprising software, hardware, and/or other logic. As used in this document, “each” refers to each member of a set or each member of a subset of a set.
Although the present invention has been described with several embodiments, a myriad of changes, variations, alterations, transformations, and modifications may be suggested to one skilled in the art, and it is intended that the present invention encompass such changes, variations, alterations, transformation, and modifications as they fall within the scope of the appended claims.
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20120032849 A1 | Feb 2012 | US |