Antenna radomes forming a cut-off pattern
First Claim
1. An antenna system comprising:
- a circularly-polarized antenna element with a Down/Up ratio between 0° and
12°
relative to a local horizon of no better than −
12 dB, andan antenna radome providing a Down/Up ratio of −
20 dB or better starting from 12° and
having transparent and semi-transparent areas, the transparent area being above the semi-transparent area.
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Accused Products
Abstract
An antenna system includes a circularly-polarized antenna element with a Down/Up ratio in a proximity of a local horizon of no better than −12 dB. An antenna radome encloses the antenna element, the radome providing a drop of antenna pattern near a local horizon and having an upper transparent area and a lower semi-transparent area. The semi-transparent area is has a generally hemispherical shape. The semi-transparent area includes a circular metallized portion with vertical and horizontal slots, the metallized portion extending part of the way downward from an equator of the generally hemispherical shape. The metallized portion includes passive discrete electrical elements connected across at least some of the slots. The metallized portion can include multiple areas having different degrees of transparence. Each such area has a specified impedance. The discrete elements are capacitors, inductors and/or resistors. The metallized portion can have a plurality of circular rows separated by the horizontal slots.
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Citations
11 Claims
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1. An antenna system comprising:
-
a circularly-polarized antenna element with a Down/Up ratio between 0° and
12°
relative to a local horizon of no better than −
12 dB, andan antenna radome providing a Down/Up ratio of −
20 dB or better starting from 12° and
having transparent and semi-transparent areas, the transparent area being above the semi-transparent area. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An antenna system comprising:
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a circularly-polarized antenna element with a Down/Up ratio between 0° and
12°
relative to a local horizon of no better than −
12 dB, andan antenna radome enclosing the antenna element, the radome providing a Down/Up ratio of −
20 dB or better starting from 12° and
having an upper transparent area and a lower semi-transparent area,wherein the semi-transparent area is has a generally hemispherical shape, and wherein the semi-transparent area includes a circular metallized portion with vertical and horizontal slots, the metallized portion extending part of the way downward from an equator of the generally hemispherical shape, and wherein the metallized portion includes passive discrete elements connected across at least some of the slots, and wherein the metallized portion has a plurality of circular rows separated by the horizontal slots. - View Dependent Claims (9, 10, 11)
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Specification