Near isotropic circularly polarized antenna

Claim 2

An antenna adapted for circularly polarized electromagnetic energy, comprising: a first hollow, electrically conductive cylinder elongated along a cylindrical axis and closed at one end thereof by a short circuiting electrically conductive wall, wherein circularly polarized electromagnetic energy propagates within said cylinder; positioned, generally equispaced circumferentially, around an outer surface of the cylinder at substantially the same axial distance therealong, a plurality of electrically conductive radiating patches each having a curvature that conforms to the curvature of said outer surface; a dielectric layer juxtaposed between said patches and said outer surface for providing electrical insulation therebetween; and coupling means situated along said outer surface beneath each patch for coupling electromagnetic energy within the cylinder to each patch and to regions outside the cylinder; wherein electromagnetic energy outside the cylinder forms a constructive radiation pattern via interaction between the patches and coupling means, so that electromagnetic energy surrounding the cylinder is circularly polarized over a substantial portion of any sphere having a center positioned at the center of said end; the coupling means comprises an elongated narrow aperture associated with each patch; each patch has the shape of a rectangular near square; and the long axis of each aperture makes nearly a 45° angle with respect to each side of its associated near square rectangular patch.

Claim 3

An antenna adapted for circularly polarized electromagnetic energy, comprising: a first hollow, electrically conductive cylinder elongated along a cylindrical axis and closed at one end thereof by a short circuiting electrically conductive wall, wherein circularly polarized electromagnetic energy propagates within said cylinder; positioned, generally equispaced circumferentially, around an outer surface of the cylinder at substantially the same axial distance therealong, a plurality of electrically conductive radiating patches each having a curvature that conforms to the curvature of said outer surface; a dielectric layer juxtaposed between said patches and said outer surface for providing electrical insulation therebetween; and coupling means situated along said outer surface beneath each patch for coupling electromagnetic energy within the cylinder to each patch and to regions outside the cylinder; wherein electromagnetic energy outside the cylinder forms a constructive radiation pattern via interaction between the patches and coupling means, so that electromagnetic energy surrounding the cylinder is circularly polarized over a substantial portion of any sphere having a center positioned at the center of said end; the coupling means comprises an elongated narrow aperture associated with each patch; each patch has the shape of a nearly circular ellipse having a major axis and a minor axis; and the long axis of each aperture makes a 45° angle with respect to each of the major and minor axes of its associated elliptical patch.

Claim 4

An antenna adapted for circularly polarized electromagnetic energy, comprising: a first hollow, electrically conductive cylinder elongated along a cylindrical axis and closed at one end thereof by a short circuiting electrically conductive wall, wherein circularly polarized electromagnetic energy propagates within said cylinder; positioned, generally equispaced circumferentially, around an outer surface of the cylinder at substantially the same axial distance therealong, a plurality of electrically conductive radiating patches each having a curvature that conforms to the curvature of said outer surface; a dielectric layer juxtaposed between said patches and said outer surface for providing electrical insulation therebetween; and coupling means situated along said outer surface beneath each patch for coupling electromagnetic energy within the cylinder to each patch and to regions outside the cylinder; wherein electromagnetic energy outside the cylinder forms a constructive radiation pattern via interaction between the patches and coupling means, so that electromagnetic energy surrounding the cylinder is circularly polarized over a substantial portion of any sphere having a center positioned at the center of said end; the coupling means comprises an elongated narrow aperture associated with each patch; each patch has the shape of a nearly circular ellipse having a major axis and a minor axis; and the long axis of each aperture makes a 45° angle with respect to each of the major and minor axes of its associated elliptical patch.

Claim 5

An antenna adapted for circularly polarized electromagnetic energy, comprising: a first hollow, electrically conductive cylinder elongated along a cylindrical axis and closed at one end thereof by a short circuiting electrically conductive wall, wherein circularly polarized electromagnetic energy propagates within said cylinder; positioned, generally equispaced circumferentially, around an outer surface of the cylinder at substantially the same axial distance therealong, a plurality of electrically conductive radiating patches each having a curvature that conforms to the curvature of said outer surface; a dielectric layer juxtaposed between said patches and said outer surface for providing electrical insulation therebetween; and coupling means situated along said outer surface beneath each patch for coupling electromagnetic energy within the cylinder to each patch and to regions outside the cylinder; wherein electromagnetic energy outside the cylinder forms a constructive radiation pattern via interaction between the patches and coupling means, so that electromagnetic energy surrounding the cylinder is circularly polarized over a substantial portion of any sphere having a center positioned at the center of said end; said antenna further comprising a second cylinder whose dimensions are frequency scaled with respect to the first cylinder, where: the first cylinder is fitted coaxially within and protrudes from the second cylinder; the second cylinder is elongated and hollow; a short circuiting electrically conducting annulus connects a first end of the second cylinder to the outside electrically conductive surface of the first cylinder; circularly polarized electromagnetic energy is present within the second cylinder; positioned, generally equispaced circumferentially, around an outer surface of the second cylinder at substantially the same axial distance therealong, are a plurality of electrically conductive radiating patches each having a curvature that conforms to the curvature of said outer surface of said second cylinder; and one of said cylinders is used for transmitting and the other of said cylinders is used for receiving.

Claim 6

An antenna adapted for circularly polarized electromagnetic energy, comprising: a first hollow, electrically conductive cylinder elongated along a cylindrical axis and closed at one end thereof by a short circuiting electrically conductive wall, wherein circularly polarized electromagnetic energy propagates within said cylinder; positioned, generally equispaced circumferentially, around an outer surface of the cylinder at substantially the same axial distance therealong, a plurality of electrically conductive radiating patches each having a curvature that conforms to the curvature of said outer surface; a dielectric layer juxtaposed between said patches and said outer surface for providing electrical insulation therebetween; and coupling means situated along said outer surface beneath each patch for coupling electromagnetic energy within the cylinder to each patch and to regions outside the cylinder; wherein electromagnetic energy outside the cylinder forms a constructive radiation pattern via interaction between the patches and coupling means, so that electromagnetic energy surrounding the cylinder is circularly polarized over a substantial portion of any sphere having a center positioned at the center of said end; said antenna further comprising a second cylinder whose dimensions are frequency scaled with respect to the first cylinder, where: the first cylinder is fitted coaxially within and protrudes from the second cylinder; the second cylinder is elongated and hollow; a short circuiting electrically conducting annulus connects a first end of the second cylinder to the outside electrically conductive surface of the first cylinder; circularly polarized electromagnetic energy is present within the second cylinder; positioned, generally equispaced circumferentially, around an outer surface of the second cylinder at substantially the same axial distance therealong, are a plurality of electrically conductive radiating patches each having a curvature that conforms to the curvature of said outer surface of said second cylinder; and one of said cylinders is used for transmitting and the other of said cylinders is used for receiving.