Dual polarized cylindrical reflector antenna system

Claim 2

An antenna system comprising a main cylindrical reflector having a parabolic cross-section and being adapted to radiate an elliptical-shaped beam originating from a point on the focal line of said reflector; first and second line sources, at least one of which is located at an actual focal line of said cylindrical reflector, wherein said first line source generates energy of one polarization and said second line source generates energy of a second polarization which is substantiAlly orthogonal to said one polarization; and polarization grating means for propagating energy of said first polarization and reflecting energy of the second polarization whereby said antenna system is capable of generating simultaneously a dual polarized, elliptically shaped beam having low cross polarization and high gain.

Claim 3

The antenna system of claim 1 wherein said main cylindrical reflector comprises a first cylindrical reflecting surface having a parabolic cross section, and a second cylindrical reflecting surface, formed by said polarization grating, having a parabolic cross section, wherein said first cylindrical reflecting surface collimates energy from said first line source and said second cylindrical reflecting surface collimates energy from said second line source, and wherein said first and second line sources are, respectively, located at the focal line of the respective first and second cylindrical reflecting surfaces.

Claim 4

The antenna system of claim 2 wherein one line source is offset from said first cylindrical reflecting surface to substantially avoid aperture blockage.

Claim 5

The antenna system of claim 3 wherein said first and second line sources are folded pill box feeds, each said pill box comprising a first and second waveguide; energy exciting means, connected to said first waveguide, for exciting energy of one polarization; a cylindrical reflector means, having a parabolic cross section for reflecting said excited energy; a flared aperture, connected to said second waveguide; and coupling slot means for coupling said excited energy from said first waveguide to said second waveguide.

Claim 6

The antenna system of claim 4 wherein one of said pill boxes generates primarily horizontally polarized energy and wherein said horizontally polarized pill box further includes means for preventing vertically polarized energy which is excited therein from being radiated by said horizontally polarized pill box.

Claim 7

The antenna system of claim 1 wherein said main cylindrical reflector comprises a single reflecting surface; and wherein said polarization grating is located between said first and second line sources; and wherein said first line source is located at the actual focal line of said single reflecting surface and radiates energy directly towards said single reflecting surface through said grating; and wherein said second line source is located at the virtual focal line of said single reflecting surface and radiates substantially all of its energy towards said polarization grating.

Claim 8

The antenna system of claim 6 wherein one of said line sources is offset from said single reflecting surface to substantially eliminate aperture blockage.

Claim 9

A dual polarization antenna system comprising: a. a main cylindrical reflector, having a parabolic cross section, comprising first and second cylindrical reflecting surfaces adapted to radiate an elliptical shaped beam originating from a point on the respective focal lines of said reflector surfaces; b. a first line source means located at the actual focal line of said first cylindrical reflecting surface, for generating linearly polarized energy, and c. a second line source means, located at the actual focal line of said second cylindrical reflecting surface, for generating linearly polarized energy which is substantially orthogonal to said first mentioned linearly polarized energy; whereby said antenna system is capable of generating simultaneously a dual polarized, elliptically shaped beam having low cross polarization and high gain.

Claim 10

A dual polarization antenna system comprising: a. a main cylindrical reflector, having a parabolic cross section, comprising first and second cylindrical reflecting surfaces adapted to radiate an elliptical shaped beam originating from a point on the respective focal lines of said reflector surfaces; b. a first line source means located at the actual focal line of said first cylindrical reflecting surface, for generating linearly polarized energy, and c. a second line source means, located at the actual focal line of said second cylindrical reflecting surface, for generating linearly polarized energy which is substantially orthogonal to said first mentioned linearly polarized energy; whereby said antenna system is capable of generating simultaneously a dual polarized, elliptically shaped beam having low cross polarization and high gain.

Claim 11

The antenna system of claim 8 wherein said first and second line source means are offset from said main cylindrical reflector to substantially eliminate aperture blockage.

Claim 12

The antenna system of claim 9 wherein each line source means comprises a folded pill box comprising: a. means for exciting polarized energy; b. a first waveguide means, connected to said means for exciting, for enabling the propagation of said polarized energy; C. a second waveguide means for enabling the propagation of said polarized energy; d. a cylindrical reflector means, having a parabolic cross section for reflecting said energy propagating in said first waveguide means; e. coupling means for coupling said reflected energy from said first waveguide means to second waveguide means; and f. a flared aperture connected to said second waveguide means.

Claim 13

The antenna system of claim 10 wherein one of said pill boxes primarily generates horizontally polarized energy and wherein said horizontally polarized line source includes means for preventing vertically polarized energy generated therein from being radiated by said horizontally polarized pill box.

Claim 14

The antenna system of claim 11 further comprising means for reducing the amount of spreading of the wavefront radiated by said pill boxes.

Claim 15

A dual polarization antenna system comprising: a. a main cylindrical reflector having a parabolic cross section, comprising a single reflecting surface adapted to radiate an elliptical shaped beam originating from the point on the focal line of said surface; b. a polarization grating means for propagating energy of a first linear polarization while reflecting energy of a second polarization which is orthogonal to said first linearly polarized energy; c. a first line source means, located at the actual focal line of said main cylindrical reflector, for radiating said first linearly polarized energy directly towards said main cylindrical reflector through polarization grating means; d. a second line source means, located at the virtual focal line of said main cylindrical reflector for radiating substantially all of said orthogonally polarized energy towards said polarization grating means; whereby said antenna system is capable of generating simultaneously a dual polarized, elliptically shaped beam having low cross polarization and high gain.

Claim 16

A dual polarization antenna system comprising: a. a main cylindrical reflector having a parabolic cross section, comprising a single reflecting surface adapted to radiate an elliptical shaped beam originating from the point on the focal line of said surface; b. a polarization grating means for propagating energy of a first linear polarization while reflecting energy of a second polarization which is orthogonal to said first linearly polarized energy; c. a first line source means, located at the actual focal line of said main cylindrical reflector, for radiating said first linearly polarized energy directly towards said main cylindrical reflector through polarization grating means; d. a second line source means, located at the virtual focal line of said main cylindrical reflector for radiating substantially all of said orthogonally polarized energy towards said polarization grating means; whereby said antenna system is capable of generating simultaneously a dual polarized, elliptically shaped beam having low cross polarization and high gain.

Claim 17

The antenna system of claim 13 wherein said first and second line source means are offset from said main cylindrical reflector to substantially eliminate aperture blockage.

Claim 18

The antenna system of claim 14 wherein each said line source means comprises a folded pill box comprising: a. means for exciting polarized energy; b. a first waveguide means, connected to said means for exciting, for enabling the propagation of said polarized energy; c. a second waveguide means for enabling the propagation of said polarized energy; d. a cylindrical reflector means, having a parabolic cross section, for reflecting said energy propagating in said first waveguide means; e. coupling means for coupling said reflected energy from said first waveguide means to second waveguide means; and f. a flared aperture connected to said second waveguide means.

Claim 19

The antenna system of claim 15 wherein said second line source means comprises a multimode, flared aperture.