Substrate-integrated-waveguide-fed cavity-backed dual-polarized patch antenna
A dual-polarized patch antenna includes a first insulating substrate; conductive connections, each of which passes through the first insulating substrate, and which are arranged to form a resonant cavity and two feeding ports; first and second metal layers respectively disposed on two opposite surfaces of the first insulating substrate, the second metal layer being formed with a cross-shaped slot that corresponds in position to the resonant cavity; a second insulating substrate disposed on the second metal layer; and four radiation patch units disposed on the second insulating substrate, and corresponding in position to four regions that are on the second metal layer and that are spaced apart by the cross-shaped slot.
1. A dual-polarized patch antenna comprising:
a first insulating substrate having a first surface, and a second surface that is opposite to said first surface of said first insulating substrate;
a plurality of conductive connections each passing through said first insulating substrate from said first surface thereof to said second surface thereof, said conductive connections being spaced apart from one another, and being arranged to form a resonant cavity, a first feeding port that is connected to said resonant cavity, and a second feeding port that is connected to said resonant cavity and that is perpendicular to said first feeding port;
a first metal layer disposed on said first surface of said first insulating substrate;
a second metal layer disposed on said second surface of said first insulating substrate, and formed with a cross-shaped slot that corresponds in position to said resonant cavity;
a second insulating substrate disposed on said second metal layer, and having a first surface that faces said second metal layer, and a second surface that is opposite to said first surface of said second insulating substrate; and
four radiation patch units disposed at intervals and symmetrically on said second surface of said second insulating substrate, and corresponding in position and respectively to four regions that are on said second metal layer and that are spaced apart by the cross-shaped slot.
2. The dual-polarized patch antenna of claim 1 , wherein a radio frequency signal is received at said first metal layer, is fed to said resonant cavity via one of said first and second feeding ports, is coupled to said radiation patch units through the cross-shaped slot, and is radiated by said radiation patch units.
3. The dual-polarized patch antenna of claim 1 , wherein the cross-shaped slot includes a first slot portion that is parallel to said first feeding port, and a second slot portion that is perpendicular to the first slot portion and that is parallel to said second feeding port.
4. The dual-polarized patch antenna of claim 3 , wherein the first and second slot portions have the same length, and the length thereof is greater than one-half of a wavelength that corresponds to an operating frequency of said dual-polarized patch antenna.
5. The dual-polarized patch antenna of claim 1 , wherein said resonant cavity is substantially square, and an operating frequency of said dual-polarized patch antenna is equal to
1
2
·
μ
·
ɛ
·
(
m
L
eff
)
2
+
(
n
L
eff
)
2
+
(
p
h
1
)
2
,
where
L
eff
=
L
cav
-
1.08
·
d
2
p
+
0.1
·
d
2
L
cav
,
L eff denotes an effective side length of said resonant cavity, L cav denotes an actual side length of said resonant cavity, d denotes a diameter of each of said conductive connections, p denotes a center-to-center distance between two adjacent ones of said conductive connections, h 1 denotes a thickness of said first insulating substrate, ε denotes a dielectric constant of said first insulating substrate, μ denotes a permeability of said first insulating substrate, m denotes a number of changes of a horizontal electric field, n denotes a number of changes of a vertical electric field,
p
d
<
3
,
d
w
<
1
5
,
and w denotes a width of each of said first and second feeding ports.
6. The dual-polarized patch antenna of claim 1 , wherein each of said radiation patch units includes a square metal plate that has a side length of
0.32
·
λ
0
ɛ
r
,
where ε r denotes a dielectric constant of said second insulating substrate, and λ 0 denotes a wavelength that corresponds to an operating frequency of said dual-polarized patch antenna.
7. The dual-polarized patch antenna of claim 1 , wherein each of said radiation patch units includes a number (N 2 ) of rectangular metal plates, where N is an integer greater than one.
8. The dual-polarized patch antenna of claim 1 , wherein said first and second feeding ports are adjacent to a corner of said resonant cavity, and multiple ones of said conductive connections at said corner are arranged to form a concave structure that recesses toward a center of said resonant cavity.
9. The dual-polarized patch antenna of claim 1 , further comprising a microstrip that is disposed on said first surface of said first insulating substrate, that is connected to said first metal layer, and that is to receive a radio frequency signal.