A geodesic antenna includes an outer cone. The geodesic antenna also includes an inner cone positioned partially within the outer cone and, together with the outer cone, defining an electromagnetic waveguide. The geodesic antenna further includes multiple driven elements configured to generate electromagnetic waves in a space between the outer and inner cones. In addition, the geodesic antenna includes a ground plane configured to reflect first electromagnetic waves of the generated electromagnetic waves back into the space between the outer and inner cones. The ground plane has a geometric design that prevents at least some second electromagnetic waves of the generated electromagnetic waves from being reflected from the ground plane and forming an interferometer pattern.

A quadrifilar helix antenna may comprise a cylindrical body with a conductive layer. The antenna may further comprise a first slot disposed on the cylindrical body, wherein a length of the first slot is proportional to a first wavelength of a first signal. The antenna may further comprise a second slot disposed on the cylindrical body. The antenna may further comprise a first feed line crossing the first slot. The antenna may further comprise a second feed line crossing the second slot.

A quadrifilar helix antenna may comprise a cylindrical body with a conductive layer. The antenna may further comprise a first slot disposed on the cylindrical body, wherein a length of the first slot is proportional to a first wavelength of a first signal. The antenna may further comprise a second slot disposed on the cylindrical body. The antenna may further comprise a first feed line crossing the first slot. The antenna may further comprise a second feed line crossing the second slot.

A slot antenna is provided with a metal cylindrical antenna element. The antenna element is formed at a height of λ/4 or less when λ is a wavelength of an antenna frequency to be used. Further, the antenna element has a slot for vertical polarization having a length of λ/2 or more in a circumferential direction.

A slot antenna is provided with a metal cylindrical antenna element. The antenna element is formed at a height of λ/4 or less when λ is a wavelength of an antenna frequency to be used. Further, the antenna element has a slot for vertical polarization having a length of λ/2 or more in a circumferential direction.

A quadrifilar helix antenna may comprise a cylindrical body with a conductive layer. The antenna may further comprise a first slot disposed on the cylindrical body, wherein a length of the first slot is proportional to a first wavelength of a first signal. The antenna may further comprise a second slot disposed on the cylindrical body. The antenna may further comprise a first feed line crossing the first slot. The antenna may further comprise a second feed line crossing the second slot.

A quadrifilar helix antenna may comprise a cylindrical body with a conductive layer. The antenna may further comprise a first slot disposed on the cylindrical body, wherein a length of the first slot is proportional to a first wavelength of a first signal. The antenna may further comprise a second slot disposed on the cylindrical body. The antenna may further comprise a first feed line crossing the first slot. The antenna may further comprise a second feed line crossing the second slot.

Technologies directed to cylindrical antenna structures. One metallic cylindrical antenna structure includes a first surface, a second surface, and a side wall with a first height. The cylindrical antenna structure can have a low profile with the first height being less than 20 millimeters (mm). The side wall includes first and second slots, the first being centered at a first point on the side wall at a second height and oriented longitudinally along an azimuthal direction of the cylindrical antenna structure and the second being centered at a second point on the side wall at the second height and oriented longitudinally along the azimuthal direction. A feed structure is located on the center axis and is physically separated from the first and second surfaces. The cylindrical antenna structure radiates electromagnetic energy in an omnidirectional radiation pattern, responsive to a radio frequency (RF) signal being applied to the feed structure.

Technologies directed to cylindrical antenna structures. One metallic cylindrical antenna structure includes a first surface, a second surface, and a side wall with a first height. The cylindrical antenna structure can have a low profile with the first height being less than 20 millimeters (mm). The side wall includes first and second slots, the first being centered at a first point on the side wall at a second height and oriented longitudinally along an azimuthal direction of the cylindrical antenna structure and the second being centered at a second point on the side wall at the second height and oriented longitudinally along the azimuthal direction. A feed structure is located on the center axis and is physically separated from the first and second surfaces. The cylindrical antenna structure radiates electromagnetic energy in an omnidirectional radiation pattern, responsive to a radio frequency (RF) signal being applied to the feed structure.

Disclosed is a wide-band conformal coaxial antenna conformal to a surface that comprises an inner conductor, an outer conductor, and a dielectric layer. The inner conductor extends towards the surface from a coaxial input below the surface and the outer conductor surrounds the inner conductor extending from the coaxial input to the surface. The dielectric layer is between the inner conductor and the outer conductor. The inner conductor has a first inner conductor diameter at the coaxial input and a second inner conductor diameter at a distal end of the inner conductor at or proximately below the surface. The inner conductor forms an inner conductor surface at the distal end of the inner conductor and the second inner conductor diameter is larger than the first inner conductor diameter. The outer conductor has a first outer conductor diameter at the coaxial input and a second outer conductor diameter at the surface. The second outer conductor diameter is larger than the first outer conductor diameter.