Cladding for a microwave antenna
View Patent ↗A cladding plate ( 2 ) for a microwave antenna has a thickness which increases with the distance r from a point of minimum thickness ( 11 ) proportional to Formula (I) wherein ∈ R is the dielectric constant of the material of the cladding plate and a is a positive constant.
1. A cladding plate for a microwave antenna, the cladding plate comprising:
a plate;
a recess formed in the plate and extending radially towards a peripheral edge of the plate from a thinnest point of the plate such that a thickness of the plate increases radially from the thinnest point in proportion to
1
1
-
(
ɛ
R
+
a
/
r
2
)
-
1
wherein r is a radial distance from the thinnest point;
wherein ∈ R is the dielectric constant of the plate material; and
wherein a is a positive constant.
2. The cladding plate of claim 1 wherein the recess is milled into the plate to form a thickness profile of the plate.
3. The cladding plate of claim 2 wherein the thickness profile of the plate increases stepwise from the thinnest point of the plate.
4. The cladding plate of claim 3 wherein a height of a step in the thickness profile is less than 100 μm.
5. The cladding plate of claim 1 wherein the plate comprises a homogeneous material.
6. The cladding plate of claim 1 wherein the plate comprises a plurality of sections.
7. The cladding plate of claim 6 wherein each section contacts each of the other sections at the thinnest point of the plate.
8. An antenna assembly comprising:
a microwave antenna;
a cladding plate configured to intersect a beam emitted by the microwave antenna, the cladding plate having a thickness d that increases with a distance r from a thinnest point of the cladding plate; and
the microwave antenna being located at a distance from the cladding plate, the distance being measured along a surface normal from the thinnest point of the cladding plate.
9. The antenna assembly of claim 8 wherein the thinnest point of the cladding plate has a thickness given by:
d
min
=
m
2
λ
0
ɛ
R
wherein m is an integer;
wherein λ 0 is an operating wavelength of the microwave antenna in a vacuum; and
wherein ∈ R is the dielectric constant of a material that comprises the cladding plate.
10. The antenna assembly of claim 9 wherein the cladding plate has a maximum thickness given by:
d
max
<
m
2
λ
0
ɛ
R
-
1
.
11. The antenna assembly of claim 8 wherein the thickness of the cladding plate increases with the distance r proportional to:
1
1
-
(
ɛ
R
+
a
/
r
2
)
-
1
,
wherein α=∈ R D 2 ;
wherein r denotes a radial distance from the point of minimum thickness of the cladding plate; and
wherein D denotes a distance of the microwave antenna from the cladding plate.
12. The antenna assembly of claim 11 the distance D is approximately 10 to 20 wavelengths of a radio signal emitted or received by the antenna.