Broad band spiral antenna with tapered arm width modulation
First Claim
1. A wide band multiarm spiral antenna for operation with both left-hand and right-hand circularly polarized radiation patterns, said spiral antenna comprising a plurality of conductive antenna arms that extend outwardly about an axis of rotation, each said antenna arm being formed by a series of cells that are configured and arranged to reflect current flowing outwardly in the antenna arm which includes those cells, the length of said cells increasing as a function of increasing distance from said axis of rotation, each said cell being configured and arranged to exhibit a monotonically decreasing electrical impedance over a first portion of the length of each said cell and a monotonically increasing electrical impedance over a second portion of said length of each said cell
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Accused Products
Abstract
Disclosed is a multiarm spiral antenna for wideband transmission and reception of both right-hand and left-hand circularly polarized electromagnetic energy. Each antenna arm includes a series of cells wherein the impedance of the antenna arm monotonically decreases over a first portion of the cell length and monotonically increases over a second portion of the cell length to thereby provide the signal reflection necessary for mode conversion (operation in both polarization senses) without introducing abrupt impedance transitions. Various cell geometry that can be employed is described.
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Citations
17 Claims
- 1. A wide band multiarm spiral antenna for operation with both left-hand and right-hand circularly polarized radiation patterns, said spiral antenna comprising a plurality of conductive antenna arms that extend outwardly about an axis of rotation, each said antenna arm being formed by a series of cells that are configured and arranged to reflect current flowing outwardly in the antenna arm which includes those cells, the length of said cells increasing as a function of increasing distance from said axis of rotation, each said cell being configured and arranged to exhibit a monotonically decreasing electrical impedance over a first portion of the length of each said cell and a monotonically increasing electrical impedance over a second portion of said length of each said cell
Specification