US 5,475,394 AGranted

Waveguide transition for flat plate antenna

AssigneeComsat Corporation

InventorsEric C. Kohls, Robert M. Sorbello, Bernard D. Geller, Francois T. Assal

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Abstract

In a flat plate antenna, insertion loss is reduced significantly by providing an extensive waveguide structure at the back of the ground plane of the antenna. Depending on antenna size, the waveguide may feed the antenna at one or a plurality of points. According to a preferred embodiment, the transition from waveguide to stripline is made via a coaxial connection, with a quarter-wave transformation, including mode suppression walls to direct the energy more efficiently. Alternatively, a direct waveguide to stripline transition may be provided. The technique has wide applicability to a number of antenna designs, including single- and dual-polarization structures, and linear and circular polarization operation.

Claims11

Dependent claims

A flat plate antenna comprising:

a ground plane;
a power distribution network layer disposed over said ground plane, said power distribution network layer comprising a central feed location, at least two power distribution lines radiating from said central feed location, and a plurality of feedlines radiating from said at least two power distribution lines;
a radiating element layer capacitively coupled to said power distribution network layer, said radiating element layer comprising a plurality of radiating elements in one-to-one correspondence with and impedance matched with said plurality of feedlines;
and
a waveguide, fastened to a side of said ground plane opposite said power distribution network layer, for feeding power to said power distribution network layer at said central feed location, said ground plane forming one wall of said waveguide, wherein said central feed location comprises E-plane bend means, disposed within said waveguide, for bending a propagation path of an output of said waveguide.

2 more elements

A flat plate antenna comprising:

a ground plane;
a first stripline power distribution network layer divided into four quadrants and disposed over to said ground plane, said first stripline power distribution network layer comprising a first central feed location and first through fourth feedpoints, one in each of said quadrants, connected to said first central feed location, at least two power distribution lines radiating from each of said first to fourth feedpoints, and a first plurality of feedlines radiating from said at least two power distribution lines;
a first radiating element layer capacitively coupled to said first stripline power distribution network layer, said first radiating element layer comprising a plurality of radiating elements in one-to-one correspondence with and impedance matched with said first plurality of feedlines;
a first waveguide, disposed on a side of said ground plane opposite said first stripline power distribution network layer, said first waveguide feeding power to said first power distribution network layer at each of said first through fourth feedpoints, each of said first through fourth feedpoints comprising a coaxial connection, and a pair of mode suppression walls on either side of each said coaxial connection, each said coaxial connection being impedance matched to said power distribution lines on said first stripline power distribution network layer;
a second stripline power distribution network layer divided into four quadrants and capacitively coupled to said first radiating element layer, said second stripline power distribution network layer comprising a second central feed location and fifth through eighth feedpoints, one in each of said quadrants, connected to said second central feed location, at least two power distribution lines radiating from each of said fifth through eighth feedpoints, and a second plurality of feedlines radiating from said at least two power distribution line;
a second radiating element layer capacitively coupled to said second stripline power distribution network layer, said second radiating element layer comprising a plurality of radiating elements in one-to-one correspondence with and impedance matched with said second plurality of feedlines;
and
a second waveguide, fastened to a side of said ground plane opposite said first stripline power distribution network layer between said ground plane and said first waveguide, and disposed orthogonally to said first waveguide, said ground plane forming one wall of said second waveguide, said second waveguide feeding power to said second power distribution network layer at each of said fifth through eighth feedpoints, each of said fifth through eighth feedpoints comprising a coaxial connection, and a pair of mode suppression walls on either side of said coaxial connection, said coaxial connection being impedance matched to said power distribution lines on said first stripline power distribution network layer.

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Dependencies are inferred from the claim text.