An Active Electronically Scanned Array (AESA) is composed of numerous
radiation elements. Due to the numerous radiation elements the AESA can
-to Se directed in a desired direction, by using a number of different frequencies
of coherent radio energy that interfere constructively at certain angles in front
of the antenna.
To achieve the desired effect, that the radio energy, from the individual
15 radiation elements, interfere constructively the radiation elements must be
positioned with an exact predetermined distance relative each other.
Normally, each radiation element is mounted at circuit board carrier which
then includes a number of radiation elements with Transmittal Receiver
Modules (TRM), distribution network, power and logic. The radiation
20 elements are mounted directly at the circuit board carrier or at a separate
board which then can be mounted on the circuit board carrier. The high
precision required in the mounting of the individual radiation elements relative
each other, results in complex mounting solutions, and thereby high costs for
the manufacturing of the mechanics, the mounting of the radiation elements
25 and the handling of the all the involved parts.
The mounting solutions used so far in the AESA, are similar to the ones used
for holding and supporting of circuit boards. With this background, the USpatent
US 4 477 135 is considered as closest prior art and discloses a
30 attachment element for mounting and holding a printed circuit board onto a
support panel, another printed circuit board or the like. The attachment
ORIGINAL
PCT/SE2009/051487
element has a unitary flange extending outwardly from it; this unitary flange is
used to attach the attachment element to a support panel or another printed
circuit board, as by welding. To mount numerous radiation elements with the
attachment element of US 4 477 135 with the high precision needed for the
5 use in a AESA would be very time consuming and expensive, since at least
two unitary retainers has to be welded with high precision for each radiation
element.
SUMMARY OF THE INVENTION
10 Therefore the object of the present invention is to provide an antenna
system, in which the radiation elements can be attached in a secure way and
with a high precision at a low cost.
The antenna system according to this invention comprises numerous
15 :adiation elements, at least one circuit board carrier, at least one circuit board
and at least one radiation element retainer device. Said radiation element
retainer device comprising an attachment means, which attaches one
radiation element to the radiation element retainer device such, that said
radiation element can be electrically connected to the at least one circuit
20 board which is arranged on the at least one circuit board carrier. The
invention is characterised in, that the radiation element retainer device further
comprising a main board on which the attaching means is located and that
one radiation element retainer device comprising a plurality of attachment
means, whereby said attachment means are integrally formed with the main
25 board, such that the attachment means and the main board consists of one
single piece of material. The attachment means and the main board together
forms the radiation element retainer device.
Due to the presented inventive construction of the antenna system, with a
30 radiation element retainer device, a plurality of radiation elements can be
quickly and with high precision mounted and fixed to the main board. The
position of the individual radiation elements, mounted on the radiation
element retainer device, relative the neighbouring radiation element is fixed.
Thereby, the needed accuracy in the positioning of the radiation elements
relative each other is guaranteed and this, to low cost and in a fast mounting
procedure. No additional positioning or fixing procedure (i.e. welding,
5 screwing, etc.) is needed, when mounting of the radiation elements.
Obviously, there are numerous alternative ways to construct the single
attachment means to achieve a fixation of the radiation element. This
~nventionis not limited to one of them, rather does it indude all attachment
10 means suitable to be integrally constructed with the main board of the
radiation element retainer device, such that the main board and the
attachment elements consists of one single piece of materiaf. One specific
construction of the individual attachment elements is shown in the figures,
several other constructions my though be suitable.
15
The attachment means of the radiation element retainer device positions the
radiation elements in the X-, Y- and Zdirection, wherein the X-, Y- and Zdirection
are perpendicular to each other. Thereby, the radiation elements
are secured in all directions, such that they are positioned with low tolerances
20 with a predetermined distance to each other. Further, the radiation elements
are fixed by the attachment means such that they can stand disturbances
which can occur in a rough surrounding, such as an aircraft flying in
turbulence, or a ship in stormy water.
25 Further, the radiation element retainer device is fabricated as of a ductile
and/or flexible material such as metal, a polymer, a carbon fibre or the like.
Thereby can the attachment means be formed such that a snap-fit
connection between the radiation element and the attachment means can be
realised, where applicable. Whereby a corresponding snap fit means is
30 formed on the radiation elements. Still, another possibility is that the radiation
element retainer device is fabricated in a stiff material, and the radiation
element is ductile andlor flexible, at least at the attachment points, such that
a snap-fit between the two is possible.
In an embodiment of the invention, the radiation element retainer device is
5 made out of a single piece of metal sheet. The profile of the attachment
means can thereby be cut out from the metal sheet, such that they can be
bended into the required position to receive the radiation element. The
cutting and bending has to be done with high precision, because of the low
tolerances for the distance between the radiation elements. Such a cutting
10 method could be laser cutting or alternatively a high precision mechanical
cutting or even punching method. Naturally, the bending of the material must
also be done with corresponding high precision to achieve the desired low
tolerances of the end product. A preferred materiel for the radiation element
retainer device is thin steel, with high flexibility; a plastic material is also a
15 possibilrty. Further materials which could be suitable are aluminium,
aluminium alloy and other light weight metallic materials.
Alternatively, the radiation element retainer device can be made out of a
polymeric material. The whole radiation element retainer device can thereby
20 be injection moulded into the required form. Thereby, the required form of the
attachment means and the main board is achieved immediately, without any
need for extensive finishing treatments.
Further, the radiation element retainer device and the attachment means can
25 alternatively be made out of carbon fibre.
Further, the circuit board carrier can be integrated with the radiation element
retainer device, such that it is made out of the same piece of material
(independent of the choice of material and manufacturing method of the
30 radiation element retainer device). Thereby can another step in the
production of the AESA be eliminated, since the radiation element retainer
device, does not have to be placed and fixed to the carrier board.
Still further, independent of the choice of material and manufacturing method,
the carrier board could alternatively be hollow. Whereby, a ventilation system
andlor cooling fluid conduit can be arranged in the hollow interior of the
5 carrier board.
For all embodiments of the radiation element retainer device, the attachment
means are arranged in one row at radiation element retainer device, such
that when the radiation elements are mounted on the main board, the
10 radiation elements are arranged in a row. Further, the attachment means can
be arranged in a plurality of rows on the radiation element retainer device
and thereby create a matrix of attachment means. The position of one
attachment means in one row can be equal to the corresponding attachment
means in a neighbouring row. Alternatively, the position of the attachment
15 means in one row can be displaced relative the corresponding attachment
means in a neighbouring row, such that a triangular matrix is created. The
more attachment means that can be arranged on one radiation element
retainer device, i.e. number of radiation elements that can be mounted on the
radiation element retainer device, the faster and easier can the mounting of
20 the numerous radiation elements on one radiation element retainer device, in
the AESA be done. Further, a high number of attachment means secures a
correct distance between all the radiation elements mounted on that radiation
element retainer device. Thereby are sources of errors which occur in the
seams between two radiation element retainer devices minimized.
25
To adjust the radiation element retainer device to be fitted in different
surroundings, i.e. a wing of an aircraft of in a spherical radome, etc, it is
provided that that the radiation element retainer device is curved in one or
two directions, such that radiation element retainer device has the form of a
30 cylinder segment or sphere segment.
To realise that the distance between a radiation element mounted last in a
row at the radiation element retainer device has a predetermined distance to
a neighbouring radiation element mounted at a neighbouring radiation
element retainer device, the radiation element retaining device has fitting
5 means arranged at its edges. The fitting means are thereby arranged in such
way, that two neighbouring radiation elements mounted in their respective
attachment means, at two different neighbouring radiation retainer devices,
are at a specific predetermined distance from each other. The predetermined
distance is preferably the same distance as the distance between two
10 radiation elements mounted in the same row at the same radiation element
retainer device.
The inventive antenna system presented above secures that the numerous
radiation elements are mounted at their respective position with the high
15 tolerances needed. The mounting can be performed quickly and to a low
cost.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure I discloses a schematic view of a radiation element retainer device.
Figure 2 discloses schematic close up view of the attachment means.
Figure 3 discloses a piece of metal sheet with cut outs.
Figure 4 discloses another schematic view of a radiation element retainer
device with an integrally formed circuit board carrier.
Figure 5 discloses a schematic view of a radiation element retainer device in
which the attachment means are arranged in a matrix.
Figure 6 discloses a schematic view of a radiation element retainer device
with the attaching means arranged in a triangular matrix.
Figure 7 discloses a schematic view of a radiation element retainer device
which is bended in one direction.
30 Figure 8 discloses a schematic view of a radiation element retainer device
which is bended in two directions.
DETAILED DESCRlPTlON OF THE DRAWINGS
In figure I is a schematic view of a part of an antenna system disclosed. The
antenna system comprises a radiation element retainer device I, numerous
5 radiation elements 3 (wherein just two is shown), at least one circuit board
carrier 4 and at least one circuit board 5. The radiation element retainer
device 1 is mounted on the circuit board carrier 4, at which a circuit board 5 is
mounted. The radiation element retainer device 1 comprises a main board 6
on which attaching means 2 are located, wherein the attaching means 2 are
10 arranged in sets 9 and each set 9 of attaching means 2 is adapted to position
and hold one radiation element 3. In figure 2, a set 9 of attaching means 2 is
disclosed. In the left side of figure 1 a neighbouring set 9' of attachment
elements 2' can be seen. Further, fitting means 11 is located at the end of the
radiation element retainer device 1. By mating the fitting means I 1 with a
15 corresponding fitting means of a neighbouring radiation element retainer
device (not shown in the figure), the fitting means I I positions the radiation
element retainer device I relative another radiation element retainer device,
such that a predetermined distance between neighbouring sets 9 of
attachment means 2 on different main boards 6 is achieved.
20
In figure 2, a piece of the radiation element retainer device 1 is shown. A set
9 of attaching means 2 is shown, which individual attaching elements 201,
202, 203 are symmetrically located on opposite sides of the symmetry line 0,
whereby the attaching elements 201,202, 203 are numbered just at one side
25 of the symmetry line 0. in this embodiment a set 9 of attachment means 2
comprises two flange supports 201 located on opposite sides of the
symmetry line 0 and two sets of clamping supports 202, 203, wherein the
wo sets of clamping supports 202, 203, are located on opposite sides of the
symmetry line 0. An alternative embodiment could have only one set of
30 clamping flange supports 202, 203, wherein they then are located in the
middle between the flange supports 201. An opening 12 is located on the
0 WO 20111078753
8
main board 6 between the flange supports 201, through the opening can the
radiation element 3 connected with a circuit board 5.
The flange supports 20land the clamping supports 202, 203 are directed
I
5 essentially perpendicular to the upper surface of the main board 6. As the
radiation element 3 is fitted into the attaching elements 2, its lower end is
guided into the correct position by the clamp supports 202, 203 and guiding -
means 204, 205 located on the flange supports 201. For this purpose the
I
I clamp supports 202, 203 have an upper shape such that the radiation
10 element easily slides in between them. The mounted radiation element 3 is
secured in the Xdirection by the guiding means 204, 205 and the clamp
P
supports 202, 203. A mounted radiation element 3 is fixed in the Z-direction
by the flange support 201. The Range support 201 has a hook 206 at its
upper part, said hook 206 and a corresponding notch in the radiation element
15 3 allows the radiation element 3 to be snap fMed into its position on the
radiation element retainer device 1. In the Y-direction the radiation element 3
is positioned and fixed by flange supports 201 through the contact with the
hook 206 and through contact along the side of the flange support 201 in
between the two guiding means 204, 205. Further is an aperture 13 for fixing
20 the radiation element retaining device 1 at for example a circuit board carrier
provided.
Figure 3 shows a piece of metal sheet 7 in which an outlined cut out 8 is
m9rked. As the cut out is performed and the waist material is removed, the
25 attachment means 2 can be bended into their required form, such as shown
in figure 2. Outlined cut out 8 shows the individual attachment elements 201-
204 as well as the opening 12 and the aperture 13
Figure 4 shows an embodiment of the radiation element attachment device 1,
30 in which the circuit board carrier 4 is integrally formed with the main board 6.
The shown embodiment could be made out of metal, plastic, carbon fibre or
another suitable material. For a metal material the circuit board carrier 4 can
be cut out in a similar process as the attachment means 2 are and thereafter
bended into the shown form, as explained in conjunction with figure 3. Wtt.l
this construction a further step in the assembly process of the antenna
system is saved, since the main board, not have to be positioned and
5 mounted on the circuit board carrier 4.
In figure 5 a radiation element retainer device 10 with a matrix of attachment
means 2 shown. By making the main board 6 lager and thereby enabling
more sets 9 of attachment means 2 to be located on the same main board 6,
10 the risk of misplacing a radiation element retainer device 1 relative its
neighbour is decreased, since fewer retainer devices 1 is needed to mount
the same amount of radiation elements 1. In figure 6 a radiation element
retainer device 10 is shown, which onfy differs from the radiation element
retainer device 10 shown in figure 5 in, that the rows of attachment means 2
15 are displaced relative the corresponding attachment means in a neighbouring
row, such that a triangular matrix is created.
Figure 7 and 8 also shows a radiation element retainer device 10 with a
matrix of attachment elements 2 arranged at a main board 6. In figure 7, the
20 main board 6 is curved in one direction, such that it forms a cylinder segment
with the radius R1. Due to the form of a cylinder segment, the radiation
element retainer device 10 can be mounted close to curved surfaces, such
within the interior of an airplane wing. In figure 8, the radiation element
retainer device 10 is curved in two directions, such that it has two bending
25 radiuses, Rl, and R2. Whereby when R1 is equal R2, the radiation element
retainer device 10 forms a sphere segment and then radiation element
retainer device 10 can be mounted close to surfaces curved in two directions,
such as a radome.

Claims
I. Antenna system, comprising numerous radiation elements (3), at least one
circuit board carrier (4), at least one circuit board (5) and at least one
radiation element retainer device (I), wherein said radiation element retainer
device (1) comprising an attachment means (2) which attaches one radiation
element (3) to the radiation element retainer device (1) such, that said
radiation element (3) can be electrically connected to the at least one circuit
board (5) which is arranged on the at least one circuit board carrier (5),
characterised in, that
the radiation element retainer device (I) further comprising a main board (6)
on which the attaching means (2) is located and that one radiation element
retainer device (1) comprising a plurality of attachment means (2)) whereby
said attachment means (2) are integrally formed with the main board (6),
such that the attachment means (2) and the main board (6) consists of one
single piece of material.
2. Antenna system, according to claim 1, wherein each attaching means (2)
positions and holds one radiation element (3) in an X-, Y- and Z-direction,
wherein the X-, Y- and 2-directions are perpendicular to each other.
3. Antenna system, according to claim 1, or 2, wherein the attachment means
(2) are formed, such that the radiation elements (3) can be snap-fitted into
position.
4. Antenna system, according to any of the preceding claims, wherein the
radiation element retainer device (1) is made out of a piece of metal sheet (7)
and thereby a profile (8) of the attachment elements (2) are - cut andlor
punched out of the piece of metal sheet (7) such that the attachment means
(2) can be bended into a position required to receive the radiation element
(3).
5. Antenna system, according to any of the claims 1 to 4, wherein the
radiation element retainer device (1) and the attachment means (2) are made
of a polymeric materiel.
5 6. Antenna system, according to claim 5, wherein the radiation element
retainer device (1) is injection moulded.
7. Antenna system, according to any of the claims 1 to 4, wherein the
radiation element retainer device (1) and the attachment elements (2) are
10 made of carbon fibre.
8. Antenna system, according to any of the preceding claims, wherein the
carrier board (4) is attached to the side of the radiation element retainer
device (Io)p posite the attachment means (2).
9. Antenna system according to claim 8, wherein the carrier board (4) is
hollow, such that a ventilation system andlor a cooling fluid conduit can be
arranged in the hollow interior of the carrier board (4).
20 10. Antenna system, according to claim 8 or 9, wherein the carrier board is
integrally formed with the radiation element retainer device (I), such that the
carrier board (4) and the radiation element retainer device (1) consists of one
single piece of material.
25 11. Antenna system, according to claim 8 or 9, wherein the carrier board (4)
is detachable attached to the radiation element retainer device (1).
12. Antenna system, according to any of the preceding claims, wherein the
attachment means (2) are arranged in one row on the radiation element
30 retainer device (I).
13. Antenna system, according to any of the preceding claims 1 to 11,
wherein the attachment means (2) are arranged in a plurality of rows on the
radiation element retainer device (I), such that a matrix (10) of attachment
means (9) is created, wherein the matrix can be a rectangular matrix or a
5 triangular matrix.
14. Antenna system, according to any of the preceding claims, wherein the
radiation element retainer device (1) is curved in one or two directions, such
that the radiation element retainer device (I) has the form of a cylinder
10 segment or sphere segment.
15. Antenna system, according to any of the preceding claims, wherein the
antenna system comprises a plurality of radiation element retainer devices
(1) and wherein fitting means (1 I) are arranged on at least one edge of the
15 radiation elements retainer devices (I) and the fitting means (1 1) locates two
neighbouring radiation retainer devices (1) in their correct position relative
each other, such that as two neighbouring radiation elements (3), are at a
specific predetermined distance from each other, wherein said two
neighbouring radiation elements (3) are located at different neighbouring
20 radiation retainer devices (1).
Dated this the 11" day of June 20 12.
(ASHISH K. SHARMA)
Of SUBRAMANIAM, NATAW & ASSOCIATES
Attorneys of the Applicants