Omnidirectional, circularly polarized, cylindrical microstrip antenna
First Claim
1. An omnidirectional, circularly polarized, antenna having at least one element comprising two concentric half-wave resonant subelements supported by a vertical conductive ground cylinder, one of said subelements being comprised of a conductive cylinder of half-wave resonant length separated from said ground cylinder by a dielectric cylinder, and the other of said subelements being comprised of a conductive sheet of half-wave resonant length, said conductive sheet being wrapped around said first subelement and separated therefrom by a dielectric cylinder, with at least two vertical radiating edges of said sheet, and means for feeding said subelements such that their far fields are subsequently equal and phased 90°
- from each other to produce a circularly polarized electromagnetic wave in the far field.
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Accused Products
Abstract
A microstrip cylindrical antenna comprised of two concentric subelements on a ground cylinder, a vertically polarized (E-field parallel to the axis of the antenna cylinder) subelement on the inside and a horizontally polarized (E-field perpendicular to the axis) subelement on the outside. The vertical subelement is a "wraparound" microstrip radiator. A Y-shaped microstrip patch configuration is used for the horizontally polarized radiator that is wrapped 1.5 times to provide radiating edges on opposite sides of the cylindrical antenna for improved azimuthal pattern uniformity. When these subelements are so fed that their far fields are equal in amplitude and phased 90° from each other, a circularly polarized EM wave results. By stacking a plurality of like antenna elements on the ground cylinder, a linear phased array antenna is provided that can be beam steered to the desired elevation angle.
45 Citations
7 Claims
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1. An omnidirectional, circularly polarized, antenna having at least one element comprising two concentric half-wave resonant subelements supported by a vertical conductive ground cylinder, one of said subelements being comprised of a conductive cylinder of half-wave resonant length separated from said ground cylinder by a dielectric cylinder, and the other of said subelements being comprised of a conductive sheet of half-wave resonant length, said conductive sheet being wrapped around said first subelement and separated therefrom by a dielectric cylinder, with at least two vertical radiating edges of said sheet, and means for feeding said subelements such that their far fields are subsequently equal and phased 90°
- from each other to produce a circularly polarized electromagnetic wave in the far field.
- View Dependent Claims (2, 3, 4, 5)
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6. An omnidirectional antenna comprised of at least one antenna element on a hollow conductive ground cylinder of a diameter about λ
-
o /12, where λ
o is the wavelength in free space of the signal to be transmitted or received, said antenna element having at least two microstrip subelements, a first subelement comprised of a dielectric cylinder concentric with said ground cylinder and a conductive sheet completely around said dielectric cylinder to form a conductive cylinder of half-wave resonant length in said dielectric, and a second subelement comprised of a second dielectric cylinder concentric with said dielectric cylinder and conductive cylinder of said first element, and a conductive sheet in a block Y shape of sufficient length to wrap one and one half times around said second dielectric cylinder with the tail between the arms thereof, said sheet having a length from the edge of the tail to the edge of the arms of half-wave resonant length in said dielectric. - View Dependent Claims (7)
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o /12, where λ
Specification