Waveguide radiator, especially for synthetic aperture radar systems
The invention relates to a waveguide radiator comprising: A slotted waveguide ( 10 ) with a plurality of slots ( 14 ) inserted in the waveguide ( 10 ); and An additional inner conductor ( 12 ) installed inside the waveguide ( 10 ), which inner conductor is shaped in a polarization-dependent manner such that all of the slots ( 14 ) of the waveguide ( 10 ) can be excited with identical phase and amplitude.
1. A waveguide radiator comprising:
a slotted waveguide with a plurality of slots inserted in the waveguide; and
a coiled inner conductor installed inside the waveguide, the coiled inner conductor being shaped in a polarization-dependent manner such that all of the slots of the waveguide can be excited with identical phase and amplitude.
2. The waveguide radiator according to claim 1 , wherein the slotted waveguide is partially filled with a dielectric material on which the coiled inner conductor is arranged.
3. The waveguide radiator according to claim 1 , wherein the coiled inner conductor is asymmetrical.
4. The waveguide radiator according to claim 1 , wherein the slotted waveguide has transversal slots, whereby the waveguide is embodied in order to radiate horizontally polarized waves.
5. The waveguide radiator according to claim 4 , wherein a feed of the waveguide is arranged asymmetrically in the longitudinal extension direction.
6. The waveguide radiator according to claim 5 , wherein the feed of the waveguide is arranged in the same such that through the feed two waveguide sections are defined in which during operation of the waveguide a wave propagates with a phase difference of approx. 180° based on the center of the waveguide.
7. The waveguide radiator according to claim 4 , wherein the coiled inner conductor comprises coil sections and a length and number of the coil sections are adapted to a spacing of the slots such that there is always a fixed number of coil sections between consecutive slots.
8. The waveguide radiator according to claim 7 , wherein a straight segment of the coiled inner conductor is arranged between the feed point and a first coil section of the coiled inner conductor.
9. The waveguide radiator according to claim 4 , wherein the coiled inner conductor has a straight inner conductor segment as an open line termination in the area of one end of the waveguide.
10. Phased array radiator with the following features:
a first waveguide radiator according to claim 4 ; and
a second waveguide radiator.
11. The phased array radiator according to claim 10 , wherein the first and second waveguide radiators are aligned longitudinally with respect to one another and have an identical length.
12. The waveguide radiator according to claim 4 , wherein the coiled inner conductor has a coil section having a rotation angle phi h and a radius x h , where
x
h
=
mea
w
k
2
+
mea
l
h
2
4
·
mea
w
h
phi
h
=
2
·
arctan
(
mea
w
h
2
·
mea
l
h
)
holds true, where mea wh defines the width of the coiled inner conductor in the coil section and mea lh the length of the coiled inner conductor in the coil section.
13. The waveguide radiator according to claim 12 , wherein the coiled inner conductor has a plurality of identical coil sections starting from a feed point arranged in a central area of the coiled inner conductor in the direction of the waveguide ends.
14. The waveguide radiator according to claim 1 , wherein the slotted waveguide has slots arranged longitudinally, whereby the waveguide is embodied to radiate vertically polarized waves.
15. The waveguide radiator according to claim 14 , wherein the coiled inner conductor has a feed point that is arranged centrally in the slotted waveguide and symmetrically to the slots.
16. The waveguide radiator according to claim 14 , wherein the coiled inner conductor has a plurality of coil sections.
17. The waveguide radiator according to claim 16 , wherein a coil section has a straight section and a curved section.
18. A waveguide radiator comprising:
a slotted waveguide with a plurality of slots inserted in the waveguide; and
an inner conductor installed inside the waveguide, the inner conductor being shaped in a polarization-dependent manner such that all of the slots of the waveguide can be excited with identical phase and amplitude,
wherein the slotted waveguide has slots arranged longitudinally, whereby the waveguide is embodied to radiate vertically polarized waves,
the inner conductor has a coiled form with a plurality of coil sections,
wherein a coil section has three curvature sections of which a first and third curvature section has respectively a first or third radius of curvature x 1 and a first or third angle of curvature phi 1v according to
x
1
=
(
mea
w
v
2
)
2
+
mea
d
v
2
2
·
mea
w
v
phi
1
v
=
2
·
arctan
(
mea
w
v
2
·
mea
d
v
)
and a second curvature section arranged between the first and third curvature section comprising two partial curvature sections with respectively one second radius of curvature x 2 and a second angle of curvature phi 2v according to
x
2
=
mea
w
v
2
+
mea
d
v
2
4
·
mea
w
v
phi
2
v
=
2
·
arctan
(
mea
w
v
mea
d
v
)
where mea wv defines a width of the additional inner conductor in the curvature section and mea dv defines a width of the curvature sections.
19. The waveguide radiator according to claim 18 , wherein the inner conductor in the area of one end of the waveguide has an open line termination, which has to a part of a coil section with a first curvature section, followed by a straight conductor segment and further followed by a second curvature section and a further straight inner conductor segment.
20. Phased array radiator comprising:
a first waveguide radiator having a slotted waveguide with a plurality of slots inserted in the waveguide and an additional inner conductor installed inside the waveguide, wherein the inner conductor is shaped in a polarization-dependent manner such that all of the slots of the waveguide can be excited with identical phase and amplitude, and wherein the slotted waveguide has transversal slots, whereby the waveguide is embodied in order to radiate horizontally polarized waves; and
a second waveguide radiator,
wherein the first waveguide radiator is arranged horizontally and vertically offset with respect to the second waveguide radiator.
21. The phased array radiator according to claim 20 , wherein an electrically conductive material is arranged in the area produced by the offset.
22. Synthetic aperture radar device, in particular a high-resolution synthetic aperture radar device, comprising a phased array radiator according to claim 20 .