Communications: radio wave antennas – Antennas – With coupling network or impedance in the leadin
Reexamination Certificate
2002-07-25
2004-07-27
Clinger, James (Department: 2821)
Communications: radio wave antennas
Antennas
With coupling network or impedance in the leadin
C343S776000, C343S778000
Reexamination Certificate
active
06768471
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to phased array antennas and, more particularly, to conformal phased array antennas and associated methods of repair.
BACKGROUND OF THE INVENTION
Antennas are widely utilized in order to transmit and receive a variety of signals. For example, antennas are prevalent in radio frequency (RF) communication systems. One common type of antenna utilized for high data rate communications with moving platforms, such as aircraft or the like, is a phased array antenna. Phased array antennas generally include a number of identical radiating elements. Each element may include a phase shifter and/or a time delay circuit. In addition, each element may include an amplifier. By adjusting the phase shift of each element, the beam transmitted and/or received by the phased array antenna may be formed electronically and steered without physical movement of the antenna aperture.
One conventional phased array antenna is depicted in FIG.
1
. As shown, the phased array antenna
100
includes a number of RF modules
102
. Each RF module generally includes a phase shifter and an amplifier. This conventional phased array antenna also includes a shim element
104
defining a number of openings
106
arranged in the predefined pattern or an array. The RF modules are therefore mounted within respective openings defined by the shim element such that the RF modules are also disposed in the predefined pattern. The phased array antenna also includes a multilayer wiring board
108
having a number of wires, conductive traces or the like. The shim element is disposed upon the multilayer wiring board such that the RF modules make contact with the multilayer wiring board and, in particular, with respective wires or conductive traces carried by the multilayer wiring board. Although not illustrated, the multilayer wiring board is also generally connected to a power supply, ground and a clock, as well as various address and data lines. The multilayer wiring board therefore supplies power, ground and clock signals to the RF modules, while permitting data to be transmitted to and from the RF modules.
The phased array antenna
100
of
FIG. 1
also includes an aperture honeycomb structure
110
having a pair of opposed planar surfaces and defining a plurality of passages
112
extending between the opposed planar surfaces. The aperture honeycomb structure defines the passages in the same configuration as the openings defined by the shim element
104
. As such, the RF modules
102
mounted within the openings
106
defined by the shim element are aligned with respective passages defined by the aperture honeycomb structure. The aperture honeycomb structure may be formed of various materials, but is typically formed of a metal, such as aluminum, a conductively coated or conductively plated plastic, a metal matrix composite or a conductively coated composite material. Dielectric inserts
114
are disposed within the passages defined by the aperture honeycomb structure. These dielectric inserts facilitate the propagation of signals through the passages such that the respective RF module may transmit and/or receive signals via the dielectric loaded passages defined by the aperture honeycomb structure. The phased array antenna also includes the wide angle impedance match (WAIM) layer
116
that overlies the outer surface of the aperture honeycomb structure. The WAIM layer is constructed from a number of dielectric layers that mitigate the impact of mutual coupling effects on aperture performance at relatively high scan angles. The phased array antenna further includes an enclosure
118
within which the other components of the phased array antenna are disposed. The enclosure protects and maintains the alignment of these other components and facilitates the mounting of the phased array antenna to a structure, such as to an airframe or the skin of an aircraft, by permitting the enclosure to be mechanically connected to the structure. While one conventional phased array antenna is depicted in FIG.
1
and described above, another phased array antenna is described by U.S. Pat. No. 5,276,455 to George W. Fitzsimmons, et al., the contents of which are incorporated herein in their entirety.
Phased array antennas are generally mounted proximate the exterior surface or skin of a structure. In order to protect the phased array antenna and to facilitate the relatively smooth flow of air thereabout, conventional phased array antennas are typically housed within an aerodynamic fairing, a radome or the like. Various types of aerodynamic fairings and radomes, such as blister or bubble radomes, can be utilized to protect the phased array antenna and to permit the relatively free flow of air therearound. Housing the phased array antenna within an aerodynamic fairing, a radome or the like is particularly advantageous in those instances in which the phased array antenna does not conformally blend into the surrounding structure.
As illustrated in FIG.
1
and as described above, the outer surface of a conventional phased array antenna is planar. In many applications, however, the phased array antenna is mounted to a structure that is not planar, but is curved or has some other contour. In these instances, a conventional phased array antenna cannot generally be mounted conformal to or flush with the surrounding surface of the structure. By housing the phased array antenna within an aerodynamic fairing, a radome or the like, however, the phased array antenna is protected.
While aerodynamic fairings, radomes and the like provide a number of advantages, these structures also create several disadvantages. In particular, aerodynamic fairings, radomes or the like increase the costs of the resulting antenna assembly. In addition, aerodynamic fairings, radomes or the like may adversely affect the RF performance of the phased array antenna. In conjunction with those phased array antennas mounted upon moving structures, such as aircraft, an aerodynamic fairing, radome or the like adds weight and imposes an aerodynamic drag penalty which, in turn, will increase fuel consumption among other things. Further, an aerodynamic fairing, a radome or the like will also disadvantageously increase the radar cross section of the structure, such as the aircraft, upon which the phased array antenna is mounted.
SUMMARY OF THE INVENTION
A phased array antenna and associated method of repairing a phased array antenna are provided to address the aforementioned and other disadvantages associated with conventional phased array antennas. In this regard, a phased array antenna of the present invention may be designed to conform with the surface or skin of the structure to which the phased array antenna is mounted. As such, the phased array antenna of the present invention need not be housed within an aerodynamic fairing, a radome or the like. Moreover, by designing the phased array antenna to have individual subassemblies or line replaceable units, the phased array antenna can be readily repaired without completely removing or deconstructing the phased array antenna.
According to one aspect of the present invention, the phased array antenna includes a planar antenna subassembly including an array of RF modules disposed in a reference plane. The planar antenna subassembly also generally includes a planar aperture honeycomb structure. The planar aperture honeycomb structure defines a number of passages in communication with respective RF modules. The phased array antenna of this aspect of the present invention also includes a contoured waveguide subassembly including a contoured aperture honeycomb structure. The contoured aperture honeycomb structure also defines a number of passages extending between the opposed first and second surfaces. The contoured aperture honeycomb structure is disposed with respect to the planar antenna subassembly such that each RF module is in communication with a respective passage of the contoured aperture honeycomb structure. In this regard, the contoured aperture honeycomb structure is ge
Bostwick Richard N.
Miller Gary E.
Rasmussen David N.
Alston & Bird LLP
Clinger James
The Boeing Company
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