Multidirectional feed and flush-mounted surface wave antenna
First Claim
1. A multidirectional antenna feed arrangement comprising:
- a ground plane including an annular cavity within the ground plane comprising a width between inner walls which approximates a quarter-wavelength of a radio wave to be launched or received by the antenna feed arrangement to prevent a shorting of the radio wave within the cavity, and an annular slot forming an opening from the cavity in a first major surface of the ground plane, the annular slot including a predetermined width which produces a predetermined capacitive reactance that is substantially balanced by an inductive reactance produced by the approximate quarter-wavelength width of the cavity in the ground plane; and
means, disposed at multiple spaced-apart locations around a first edge of the annular slot, and capable of simultaneously delivering or receiving a radio frequency message signal to or from multiple locations around the annular slot for exciting or extracting a corresponding radio wave in the cavity and slot and launching or receiving said radio wave from the slot.
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Accused Products
Abstract
The present invention relates to a multidirectional feed which can be used by itself or preferably incorporated within a surface wave structure to form a flush-mounted antenna on, for example, a mobile unit. The feed arrangement comprises a ground plane including an annular cavity with a smaller annular slot. The annular slot is connected by multiple, spaced-apart, leads to an associated transceiver. The annular cavity is also formed to prevent both a shorting of the radio waves therein and the radio waves from propagating away from the cavity in a direction opposite the slot. A surface wave structure is disposed preferably with the feed centrally mounted and can comprise any suitable structure including annular corrugations and/or a dielectric layer to provide a flush-mounted antenna arrangement which provides radiation in azimuth in all directions with moderate elevation gain.
228 Citations
10 Claims
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1. A multidirectional antenna feed arrangement comprising:
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a ground plane including an annular cavity within the ground plane comprising a width between inner walls which approximates a quarter-wavelength of a radio wave to be launched or received by the antenna feed arrangement to prevent a shorting of the radio wave within the cavity, and an annular slot forming an opening from the cavity in a first major surface of the ground plane, the annular slot including a predetermined width which produces a predetermined capacitive reactance that is substantially balanced by an inductive reactance produced by the approximate quarter-wavelength width of the cavity in the ground plane; and means, disposed at multiple spaced-apart locations around a first edge of the annular slot, and capable of simultaneously delivering or receiving a radio frequency message signal to or from multiple locations around the annular slot for exciting or extracting a corresponding radio wave in the cavity and slot and launching or receiving said radio wave from the slot. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification