Abstract: A monopole antenna, comprising: a radiating element, wherein the radiating element has a first curved outer surface that is rotationally symmetric about a longitudinal axis extending through the monopole antenna, wherein a first diameter at a first end of the radiating element is less than a second diameter at a second end of the radiating element; and a ground plane disposed opposite the radiating element such that an electric field is generated by the radiating element with a ground plane providing the counterpoise, wherein the ground plane has a second curved outer surface that is rotationally symmetric about the longitudinal axis, wherein a first diameter at a first end of the ground plane is less than a second at a second end of the ground plane, wherein the first end of the radiating element is disposed adjacent the first end of the ground plane.

Abstract: A monopole antenna, comprising: a radiating element, wherein the radiating element has a first curved outer surface that is rotationally symmetric about a longitudinal axis extending through the monopole antenna, wherein a first diameter at a first end of the radiating element is less than a second diameter at a second end of the radiating element; and a ground plane disposed opposite the radiating element such that an electric field is generated by the radiating element with a ground plane providing the counterpoise, wherein the ground plane has a second curved outer surface that is rotationally symmetric about the longitudinal axis, wherein a first diameter at a first end of the ground plane is less than a second at a second end of the ground plane, wherein the first end of the radiating element is disposed adjacent the first end of the ground plane.

Abstract: A spiral antenna, comprising a first arm and a second arm. The first arm and second arm are interlaced with each other. Each arm has a plurality of turns comprising an inner subset of circular turns, and an outer subset of turns, electrically coupled to the inner subset, having a shape with only four lines of symmetry. An array of such spiral antennas disposed a substrate that extends in a direction of a longitudinal axis and having a round cross section in a plan transverse to the longitudinal axis.

Abstract: A spiral antenna, comprising a first arm and a second arm. The first arm and second arm are interlaced with each other. Each arm has a plurality of turns comprising an inner subset of circular turns, and an outer subset of turns, electrically coupled to the inner subset, having a shape with only four lines of symmetry. An array of such spiral antennas disposed a substrate that extends in a direction of a longitudinal axis and having a round cross section in a plan transverse to the longitudinal axis.