Cladding for a microwave antenna
View Patent ↗A cladding ( 2 ) for a microwave antenna comprises at least one plate ( 3 a, 3 b, 3 c, 3 d ) which has, in a first section plane (x=0; y=0), a cross section in the shape of a logarithmic spiral, characterized in that the plate ( 3 a, 3 b, 3 c, 3 d ) has a cross section in the shape of a logarithmic spiral also in at least one second section plane perpendicular to the first one.
1. A cladding for a microwave antenna, the cladding comprising:
at least one plate having a first section plane and at least one second section plane perpendicular to the first section plane; and
the plate having a cross section in the shape of a logarithmic spiral in each of the first and second section planes.
2. The cladding of claim 1 wherein:
the logarithmic spirals of the first and second section planes have a common vortex at r=0; and
the radius r of the spirals is given by r(φ)=r 1 *e aφ and r(ψ)=r 2 e aψ , respectively, where φ, ψ are angles in the first and second section planes, respectively, and r 1 , r 2 and a are constants.
3. The cladding of claim 2 wherein r 1 =r 2 , and wherein the plate has a shape given by r(φ,ψ)=r 1 *exp(a√{square root over (φ 2 +ψ 2 ))}, where a is the square root of the dielectric constant ∈ R of the material of the plate.
4. The cladding of claim 2 wherein the plate has a shape given by r(φ,ψ)=r 0 * e aφ * e aψ , where a is the square root of the dielectric constant ∈ R of the material of the plate.
5. The cladding of claim 1 further comprising a plurality of continuously joined plates, each plate having a cross section in the shape of a logarithmic spiral.
6. The cladding of claim 5 wherein the logarithmic spiral-shaped sections of a pair of the continuously joined plates have a common vortex at r=0.
7. The cladding of claim 6 wherein the pair of plates is joined in a first junction plane (x=0; x=y) extending through the vortex.
8. The cladding of claim 7 wherein the pair of plates is further joined along a second junction plane (y=0) extending through the common vortex (r=0) perpendicular to the first junction plane (x=0).
9. The cladding of claim 7 wherein the first junction plane is the first section plane.
10. The cladding of claim 7 wherein the first junction plane (x=y) bisects an angle formed by the first and second section planes (x=0, y=0).
11. An antenna assembly comprising:
a cladding comprising:
a plate having a first section plane and a second section plane perpendicular to the first section plane; and
the plate having a cross section in the shape of a logarithmic spiral in each of the first and second section planes; and
an antenna positioned at a common vortex of the logarithmic spirals.
12. The antenna assembly of claim 11 wherein:
the logarithmic spirals of the first and second section planes have a common vortex at r=0; and
the radius r of the logarithmic spirals of the first and second section planes is given by r(φ)=r 1 *e aψ and r(ψ)=r 2 e aψ , respectively, with φ, ψ being angles in the first and second section planes, respectively, and r 1 , r 2 and a being constants.
13. The antenna assembly of claim 12 wherein r 1 =r 2 , and wherein the plate has a shape given by r(φ,ψ)=r 1 *exp(a√{square root over (φ 2 +ψ 2 ))}, where a is the square root of the dielectric constant ∈ R of the material of the plate.
14. The antenna assembly of claim 12 wherein the plate has a shape given by r(φ,ψ)=r 0 * e aφ * e aψ , where a is the square root of the dielectric constant ∈ R of the material of the plate.
15. The antenna assembly of claim 11 wherein the cladding further comprises a plurality of continuously joined plates, each plate having a cross section in the shape of a logarithmic spiral.
16. The antenna assembly of claim 15 wherein the logarithmic spiral-shaped sections of a pair of the continuously joined plates have a common vortex at r=0.
17. The antenna assembly of claim 16 wherein the pair of plates is joined in a first junction plane (x=0; x=y) extending through the vortex.
18. The antenna assembly of claim 17 wherein the pair of plates is further joined along a second junction plane (y=0) extending through the common vortex (r=0) perpendicular to the first junction plane (x=0) .
19. The antenna assembly of claim 17 wherein the first junction plane is the first section plane.
20. The antenna assembly of claim 17 wherein the first junction plane (x=y) bisects an angle formed by the first and second section planes (x=0, y=0).