Communications: directive radio wave systems and devices (e.g. – Directive – Including a steerable array
Reexamination Certificate
1999-11-24
2001-01-16
Tarcza, Thomas H. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Directive
Including a steerable array
C342S372000
Reexamination Certificate
active
06175330
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an array antenna, comprising a set of radiators for the transmission or reception of microwave radiation, which radiators are distributed at least substantially homogeneously within the volume of an imaginary three-dimensional body, preferably spherical in shape, where each individual radiator is via an adjustable phase shifter connected to a transmitting network to choose a direction in which microwave radiation can be transmitted.
2. Discussion of the Background
An array antenna of this type is known from DE-A 28.22.845. For fire-control applications, however, this known array antenna is unsuitable for determining the position of a target with sufficient accuracy. For an accurate determination, it is required to generate for a target the error voltages known in the art, for instance in azimuth and elevation, for instance under the application of a monopulse antenna.
An array antenna of the monopulse type is known from patent specification EP-B 0.207.511. The spherical antenna disclosed in this specification is divided into eight octants by means of which the error voltages are determined by combining the output signals of the eight octants. The known array antenna is most satisfactory if a target is situated on an intersecting line of two dividing planes between the octants, because this would imply symmetry between the various antenna parts. For targets that do not fulfil this condition, the array antenna performance is suboptimal.
SUMMARY OF THE INVENTION
The array antenna according to the invention obviates this drawback and is characterized in that to enable reception, the set of radiators is divided into two, three or four subsets, that for each subset the radiators are distributed at least substantially homogeneously within the body and that there are provided two, three or four receiving networks connected to the subsets for simultaneously choosing two, three or four directions from which microwave radiation can be received.
The invention additionally relates to a method for operating an array antenna, comprising a set of radiators for the transmission or reception of microwave radiation, which radiators are distributed at least substantially homogeneously within the volume of an imaginary three-dimensional body, preferably spherical in shape, whereby in a transmit mode, a transmitter signal is applied, via adjustable phase shifters and a transmitting network, to at least substantially all radiators for generating a microwave beam in a predetermined direction.
The inventive method is characterized in that in a receive mode, two, three or four subsets of at least substantially equal numbers of radiators are combined via adjustable phase shifters and two, three or four receiving networks for choosing two, three of four directions from which microwave radiation can be received.
A favourable realization of the method is characterized in that in the transmit mode, the microwave beam is directed at a target and that in the receive mode, the two, three or four directions are chosen such that the output signals of the two, three or four receiving networks can be combined to yield a sum signal and at least one difference signal.
REFERENCES:
patent: 4626859 (1986-12-01), Stansfield
patent: 5010343 (1991-04-01), Andersson
patent: 5038149 (1991-08-01), Aubry et al.
patent: 5122808 (1992-06-01), Kyriakos
patent: 5767805 (1998-06-01), Aubry
patent: 0207511 (1987-01-01), None
Hollandse Signaalapparaten B.V.
Oblon, Spivak, McClelland, Maier & Neustadt
Phan Dao L.
Tarcza Thomas H.
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