Communications: radio wave antennas – Antennas – Microstrip
Reexamination Certificate
2000-03-09
2001-12-04
Wong, Don (Department: 2821)
Communications: radio wave antennas
Antennas
Microstrip
C343S878000, C343S835000
Reexamination Certificate
active
06326920
ABSTRACT:
TECHNICAL FIELD
This invention pertains to high-frequency, e.g., microwave, antennas.
BACKGROUND OF THE INVENTION
The recent proliferation of, and resulting stiff competition among, wireless communications products have led to price/performance demands on microwave/millimeter-wave antennas that conventional technologies find difficult to meet. This is due in large measure to high material costs and to high losses in the feed network which must be compensated for. Other problems include expensive manufacturing operations such as milling, hand-assembly, and hand-tuning, and the high numbers and required precision of metal and dielectric parts which are needed to construct these antennas.
High-volume manufacturing techniques have reduced the costs of some conventional antennas, such as the patch arrays that are used in wireless telephone systems and the off-axis parabolic dishes that are extensively used for satellite television reception. However, these techniques do nothing to improve the performance of these antennas, nor do they improve the costs of low- and medium-volume antennas. The need for low-cost high-frequency antennas has also been addressed by using “corporate feed” patch arrays printed on PC boards. Problems with this approach include large losses in the feed array, mostly due to dielectric losses in the PC board, and the high cost of the PC board itself. The losses limit the antenna's usefulness and either degrade the net performance or increase the cost of the associated transmitter and/or receiver.
SUMMARY OF THE INVENTION
This invention is directed to solving these and other problems and disadvantages of the prior art. According to the invention, an antenna is made from a single sheet of electrically conductive material, e.g., metal, such as aluminum or steel, preferably by stamping. This simple one-metal-layer antenna contains both the radiator elements and the feed (distribution) network of the antenna. These elements and network are contained within, and are attached by integral supports to, a metal frame which is also an integral element of the same layer, and form a self-supporting patch array antenna. The supporting structure also provides the necessary spacing between the radiator elements and a ground plane. The antenna can be mounted by the frame over any ground plane, e.g., an outside wall of an equipment enclosure, a single sheet of metal, or a PC board. Preferably, the antenna is stamped from the single sheet along with integral second supports that connect the radiators and feed network to each other and to the frame and provide rigidity during manufacture and assembly. The frame is preferably bent relative to the radiating elements to effect the spacing of the radiating elements from the ground plane, and the frame is mounted to the ground plane. Alternatively, that portion of the frame which lies at an angle to the plane of the radiating elements and the feed network and provides the spacing is manufactured separately, i.e., by stamping, molding, or extrusion, and is mounted to both the other portion of the frame and to the ground plane. Any second supports are then removed, e.g., cut or broken off. Preferably, the feed network is positioned closer to the ground plane than the radiating elements; this is achieved by bending the metal that forms the feed network.
Major benefits of the invention over conventional antenna designs include fewer parts, fewer process steps, easier assembly, higher performance (less loss and fewer patch elements for the same gain), higher gain for the same area and therefore smaller size, compact flat-panel form-factor, and lower cost. These and other features and advantages of the invention will become more apparent from a description of an illustrative embodiment of the invention considered together with the drawing.
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Barnett Ron
Korisch Ilya Alexander
Wu Hui
Avaya Technology Corp.
D Chuc Tran
Volejnicek David
Wong Don
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