The invention relates to a dual-polarization and dual-band microstrip antenna comprising a circuit for transmitting electromagnetic waves and a circuit for receiving electromagnetic waves formed by a stack of four dielectric substrates

1. Dual-polarization and dual-band microstrip antenna
The invention relates to a dual-polarization and dual-band microstrip antenna comprising a circuit
for transmitting electromagnetic waves and a circuit for receiving electromagnetic waves formed
by a stack of four dielectric substrates (1, 2, 3, 4), namely: a first substrate (4) having a first side
(4b) covered with four microstrips, two first strips belonging to the transmitting circuit and the
two other strips belonging to the receiving circuit; a second substrate being covered with two
metallization pads (m3, m4); a third substrate being covered with a metal disk (D); the fourth
substrate (1) being covered with a ring-shaped metallization (A) and two additional metallization
pads (m1, m2), holes (H10, H8, H4, H2) being formed in the substrates in order to allow
conductive wires to pass, on the one hand between the ends of two first lines and the two pads,
and on the other hand between the ends of two other lines and the two additional pads.
1. A microstrip antenna dual-polarization and dual band comprising an electromagnetic wave
transmission circuit and an electromagnetic wave receiving circuit formed by a stack of four
dielectric substrates (1, 2, 3, 4) each having a first face and a second face opposite the first face,
the first face (4b) of a first substrate (4) being covered four microstrip lines, first two microstrip
lines being aligned along a first axis and two second microstrip lines being aligned along a
second axis perpendicular to the first axis, the ends of the microstrip lines being positioned
symmetrically with respect to a point of intersection of the first and second axes, the first two
adjacent lines at right angles forming the input ports of the circuit emission, the other two
adjacent lines at right angles forming the output ports of the receiving circuit, the second face
(4a) of the first substrate (4) being covered by a metallisation constituting an antenna ground
plane and being attached to the first face of a second substrate (3), the first face is covered with
two metallization pads (m3, m4) positioned, each substantially vertically from one end of a line
constituting a port of different entry, the second surface of a third substrate (2) being covered
with a metal disc (D) and being fixed on the first side of a fourth substrate (1) of which the
second face is covered with a metallization ring form (a) substantially centered vertically of the
metal disk (D) and two additional metallization pads (ml, m2) positioned, each substantially
vertically from one end of a line connected to a port different output, an inner radius (RI) of the
ring (a) being greater than a radius (R3) of the metal disk (D), holes (H10, H8, H4, H2) being
formed in the substrate in order to ensure the passage of a conductor wire on the one hand,
between each of the ends of two adjacent lines at right angles that are the input ports of the
antenna and a different metallization pad present on the second face of the second substrate and,
secondly, between each of the ends of two adjacent lines at right angles that constitute the
antenna output ports and a different additional metallization pad (ml, m2).
2. A microstrip antenna according to claim 1, wherein a foam layer (F) is placed between the
third substrate (2) and the fourth substrate (1), through holes (HM1, HM2) being formed in the
foam layer for passing the conductors son which connect the ends of two adjacent lines at right
angles that are the output ports of the antenna to the additional metallization pads (ml, m2).

2. 3. A microstrip antenna according to claim 2, wherein the transmitted electromagnetic waves are
substantially between 14GHz and 14,5GHz and the received electromagnetic waves are
substantially between 12 and 10,7GHz, 75GHz.
ANTENNA MICROSTRIP DOUBLE BIAS DUAL BAND
DESCRIPTION
Technical field and prior art
The invention relates to a dual-polarized microstrip antenna and dual band capable of receiving
and transmitting signals.
A field of application of the antenna of the invention is to transmit / receive signals from a
geostationary satellite to mobile platforms such as, for example, airplanes, trains, boats, etc.
The antenna of the invention is intended to be used in phased array antennas. The phased array
antenna uses the principle of semi-electronic scanning wherein a small fraction of the angular
variation of the transmitted wave is made by electronic scanning, the remainder of the change
being effected by mechanical means. A sweep limitation is due to the nature of reason to the
radiator.
Of phased array antennas have been developed using planar microstrip antennas printed dipoles.
The gain of a planar antenna microstrip printed dipole decreases when the sweep angle deviates
from the direction perpendicular to the axis of the dipoles. This results in a decrease of the
equivalent isotropically radiated power for large scan angles. Mechanical devices are then
designed to tilt the antenna structure. In addition, microstrip antennas are inherently low
bandwidth due to the very high Q resonators. This is also another drawback.
The antenna microstrip dual-polarization and dual band of the invention does not have the
disadvantages mentioned above. Indeed, the dual-polarized microstrip antenna and dual band of
the invention has a bandwidth which corresponds advantageously to the drawbacks mentioned
above.
Disclosure of Invention
Indeed, the invention relates to a dual-polarized microstrip antenna and dual band comprising an
electromagnetic wave transmission circuit and an electromagnetic wave receiving circuit formed
by a stack of four dielectric substrates each having a first face and a second face opposite the first
face, the first face of a first substrate being covered four microstrip lines, first two microstrip
lines being aligned along a first axis and two second microstrip lines being aligned along a
second axis perpendicular to the first axis, the ends of the microstrip lines being positioned
symmetrically with respect to a point of intersection of the first and second axes, the first two
adjacent lines at right angles forming the input ports of the transmission circuit, the other two
adjacent lines at angle duty constituting the output ports of the receiving circuit, the second face
of the first substrate being covered by a metallisation constituting an antenna ground plane and
being attached to the first face of a second substrate, the first face is covered with two
metallization pads positioned, each substantially vertically from one end of a line constituting a
different input port, the second surface of a third substrate being covered with a metal disc and
being attached to the first side of a fourth substrate having the second face is covered with a
metallization shaped ring centered substantially vertically above the metal disk and two
additional metallization pads positioned, each substantially vertically from one end of a line

3. connected to a different output port, an inner radius of the ring being greater than a radius of the
metal disc, the holes being formed in the substrates to ensure the passage of a conductor wire on
the one hand between each of the ends of two adjacent lines at right angles that constitute the
antenna input ports and a different metallization pad present on the second face of the second
substrate and, secondly, between each end of the two adjacent lines at right angles that constitute
the antenna output ports and a different additional metallization pad.
According to yet another characteristic of the invention, a foam layer is placed between the third
substrate and the fourth substrate through holes being formed in the foam layer for passing
drivers son.
BRIEF DESCRIPTION OF FIGURES
Other characteristics and advantages of the invention appear on reading a preferred embodiment
given with reference to the accompanying drawings, in which:
- Figures 1-4B represent elements of a dual-polarized microstrip antenna and dual band according
to the preferred embodiment of the invention;
- Figures 5 and 6 show side views, in two perpendicular directions, a dual-polarized microstrip
antenna and dual band made from the constituent elements shown in FIGS 1-4B, according to a
first embodiment of the invention; and
- Figures 7 and 8 are side views, in two perpendicular directions, a dual-polarized microstrip
antenna and dual band made from the components shown in Figures 1-4B, in a second
embodiment of the 'invention.
In all the figures, the same references designate the same elements.
Detailed Description of œuyre in embodiments of one invention
1 shows a top view of a first constituent element of the antenna of the invention. The first
member is a dielectric substrate 1 on one face of which is printed a circular metal ring A. The
upper and lower faces of the dielectric substrate 1 has a square shape of side (e.g., d = 30mm).
The circular ring A is preferably centered on the upper face of the substrate 1. The lower face is
void of any metallization. The inner radius RI of the ring A taken with respect to the center of the
upper face of the substrate 1 is, for example, equal to 2.6 mm and the outer radius R2, taken from
the same center, is for example equal to 3 , 5mm. Two metallizations ml, m2 are formed near the
ring A. The metallizations ml, m2 are positioned substantially at right angles to one another. The
distance 1 between each metallization of the ring A is substantially equal to 0.15mm.
Interconnection opening holes Hl, H2, preferably centered on the metallizations ml, m2, pass
through the substrate 1. The metallizations ml and m2 are, for example, a rectangle shape axb (a
= 18mm and b = 9mm).
2 shows a second element of the antenna of the invention. The second member is a dielectric
substrate 2 of a first face of which is printed a metal disc D substantially centered, the face
opposite the first face being devoid of metallization. The upper and lower faces of the dielectric
substrate 2 forms a square of side (e.g., d = 30mm). The radius R3 of the metal disc D is, for
example, equal to 2.3mm. Through holes H3, H4 through the substrate 2. The through-holes H3,
H4 are positioned on the side of the substrate 2 in a manner substantially identical to the manner
in which the through holes are positioned on the face of the substrate 1.
3 shows a third constituent element of the antenna according to the invention. The third element
is a dielectric substrate 3 on one face of which are printed two metallizations m3, m4, the face
opposite to the face where the two metallizations are printed m3, m4 being devoid of
metallization. The through vias H5, H6 pass through the substrate 3 at the respective

4. metallizations m3, m4. The dielectric substrate 3 preferably has upper and lower faces of
identical square shape of side to side of the dielectric substrates 1 and 2. The metallizations m3
and m4 have a shape of rectangle × j (i = j = 16mm and 6mm). Positions metallizations m3, m4
and the through holes H5, H6 are specified later with reference to Figures 5 and 6 which show
side views of the complete structure of the antenna.
4A and 4B show, respectively, a first face 4a a fourth dielectric substrate 4 and a second face 4b
of the fourth dielectric substrate 4 opposite to the first face. The substrate 4 is preferably of
dimensions greater than the dimensions of the substrates 1, 2 and 3. The side The upper and
lower faces of the substrate 4 is thus equal, for example, to 40mm when the side of the substrates
1, 2 and 3 is equal to 30mm. The first face 4 is entirely covered with a metallization (Figure 4)
and the face 4b opposite to the face 4 is covered with four microstrip lines arranged at right
angles, first two lines and lg3 lgl being aligned along an axis X-Xl and the other two lg2 and LG4
lines being aligned along a Y-axis Yl perpendicular to the axis X-Xl. The ends of lgl-LG4
microstrip lines are positioned symmetrically relative to the axes of the intersection point X-Y-Xl
and Yl, preferably equidistant from the intersection point. Four non holes H9, H10, Hll, H12 are
drilled into the substrate 4 from the face 4a and 4b to the face, it is not breakthrough. H12 and
H10 the holes are aligned along the axis X-XI and the H9 and Hll holes are aligned along the axis
Y-Yl. The H12 and H9 holes are at the same distance g from the point of intersection of the axes
X, Xl and Yl and Y H10 and Hll holes are at the same distance k of the axes intersection point X-
XI and Y yl. The distance g is, for example, equal to 16mm and the distance k, for example,
equal to 34,5mm. The four holes H9-H12 does not have the same diameter: the H12 and H9 holes
have, for example, a diameter of 8mm and the holes H8 and Hll have, for example, a diameter of
13mm. H9 and H12 holes have a strong influence on the antenna reflection coefficient. This is
why their diameter should be particularly optimized.
5 shows a first side view of an antenna according to a first embodiment of the invention,
constructed from the elements shown in FIGS 1-4B. FIG 5 is a view along the axis X-Xl.
The antenna of the invention results from the stack of substrates 1, 2, 3 and 4 described above
and a layer of foam F. different substrates and the foam layer are stacked such that:
- The face 4a of the substrate 4 covers the face devoid of metallization of the substrate 3, the hole
H12 is opposite the hole H5 and H10 hole being next to the hole H8,
- The free face metallization of the substrate 2 covering the face provided with metallization of
the substrate 3, the hole H4 of the substrate 2 being opposite the hole
H8 of substrate 3,
- The face of the substrate 2 provided with the metallic disk covers the first face of the foam layer
F, the hole H4 of the substrate 3 being opposite a first through hole formed in the HML foam
layer
F, and
- The second face of the foam layer, located opposite the first face, is covered by the layer of the
substrate 1 devoid of metallization, the hole H2 of the substrate 1 being opposite the first hole
HML which is formed in the foam layer.
Different substrates are attached to each other by any means known per se.
The table below gives, by way of non limiting example, the values of the thicknesses of 1,2,3,4
dielectric substrates so that the values of relative dielectric constants of the materials constituting
these substrates:

5. Board
For the values mentioned above, the foam layer F has a thickness equal to 2 mm and a relative
dielectric constant ε Γ equal to 1.06.
A first electrically conductive fl wire electrically connects the lg3 metallization to the
metallization m3 and a second f2 electrically conductive wire electrically connects the lgl
metallization metallization m2. The son fl and f2 are welded to different metallization to provide
the desired electrical contact between son and metallization. The son fl and f2 are, for example,
copper son of a very small diameter.
6 shows another side view of an antenna according to the first embodiment of the invention
constructed from the elements shown in Figures 1-4B. Figure 6 is a view along the axis Y-Yl.
The side view reveals that:
- The hole H9 is opposite the hole H6 and Hll hole faces the hole H7; - H7 hole faces the hole H3
and the hole H3 is opposite a second through hole HM2 formed in the foam layer F; and
- The second through hole HM2 is opposite the hole Hl.
A third f3 electrically conducting wire connects the m4 LG4 metallization metallization and a
fourth electrically conductive wire connects the f4 lg2 metallization metallization ml. F3 and f4
son are welded to different metallization to provide electrical contact between desired son and
metallization. F3 and f4 son are, for example, copper son of a very small diameter.
The antenna of the invention works in two different frequency bands, namely 10,7GHz band -
12,75GHz reception and 14GHz band
- 14,5GHZ broadcast. The lgl lg2 and metallization are the output ports of the reception antenna
and the metallized lg3 LG4 and form the input ports of the broadcast antenna. Metallizations ml,
m2 are excitation elements of the ring A and the metallizations m3, m4 are the disc excitation
elements D. The two microstrip lines used for each of the two operating modes (lg3 lines, LG4
for transmission and lgl lines lg2 for reception) are perpendicular to each other to obtain the
desired dual polarization (vertical linear polarization and horizontal). In transmission, at least one
of the two LG3 and LG4 ports is excited by a transmit signal, or according to the required
polarization (s) for transmission. In reception, the signals arriving on lgl and lg2 ports are
transmitted to the processing circuits based on their polarization.
The antenna according to the first embodiment of the invention described with reference to
Figures 5 and 6 comprises, in addition to the substrates 1, 2, 3, 4, a foam layer F between the
substrates 1 and 2. The foam layer F has the advantage of increased bandwidth of the antenna
(decay factor Q). In applications requiring smaller bandwidths, the antenna can not understand no
foam layer. Figures 7 and 8 illustrate the second embodiment of the invention in which the
substrate 2 is directly in contact with the substrate 1.