FR3079677A1 - WIRELESS COMMUNICATION DEVICE INTEGRATING A PLURALITY OF CORNEAL ANTENNAS ON A PRINTED CIRCUIT (PCB), METHOD FOR THE PRODUCTION AND USE THEREOF - Google Patents

Abstract

The present invention relates to a wireless communication device comprising: - a printed circuit (PCB) comprising a dielectric support and electrically conductive tracks separated by the dielectric support; at least one horn antenna. The horn antenna is a surface mounted component (CMS) via flange (s) supported by the PCB and fixed on the latter, and the horn antenna is arranged with the waveguide and the radiating aperture on either side of the PCB and with each rib in direct contact or near a track of the PCB, so as to allow a direct connection or a capacitive coupling between them.

Description

WIRELESS COMMUNICATION DEVICE INCLUDING A PLURALITY OF CORNER ANTENNAS ON A PRINTED CIRCUIT (PCB), METHOD FOR THE PRODUCTION AND USE THEREOF

Technical area

The present invention relates to wireless communications devices with antenna (s) -cornet (s), more particularly intended to ensure communications in the millimeter frequency bands.

The invention more specifically aims to improve the integration of one or more horn antennas on a printed circuit (in English "Printed Circuit Board" acronym PCB).

It also relates to the associated production method and advantageous use.

Prior art

In the context of digital wireless communications, many applications require the transfer of very large volumes of wireless and high-speed data in an increasingly short time between different communicating objects.

This translates into a demand for much higher wireless communications system throughput capacity. An increase in bitrate is in particular necessary for the development of new applications, such as "Wireless HD" which must make possible the wireless transmission of large volumes of data, such as "uncompressed" high definition video at very high bitrate , typically 1 to 2 Gbits / s.

This demand has given rise to the emergence and development of new communication technologies operating in the millimeter frequency band, from 30 to 300 GHz, in order to ensure high speeds, these frequency bands having previously been reserved essentially for military or scientific systems. using expensive technologies.

In particular, it seems to be accepted that the frequency band of the order of 60 GHz, known as the V band, is a preferred solution, because of its frequency bandwidth, of the order of 10 GHz, making it possible to obtain bit rates up to 6 Gbits / s.

Such a bit rate is appreciable for making wireless links for short ranges, typically of the order of a meter, which can replace wired solutions, such as HDMI (acronym for "High Definition Multimedia Interface") or USBC. (Acronym for Universal Serial Bus Type C).

The development of these new communication technologies has given rise to increasingly efficient electronic circuits for the integration of millimetric transceiver systems.

This is also true for antennas as they are essential components in transceiver systems. Thus, the miniaturization and performance of the antennas are essential for their integration into current and future transceivers.

It is already known that a horn antenna can be a response to this demand by its intrinsic compactness, its good radio performance, but above all by its low losses in the millimeter frequency bands.

It will be recalled here that a horn antenna is a guide device with progressive section consisting of a straight wave guide, for example of rectangular section, extended at one of its ends by a radiating opening of general truncated cone shape. or truncated pyramid. An advantageous type of horn antenna is one with one or more ribs inside the opening, which increases the bandwidth of the antenna.

That said, the solutions proposed to date for the creation and integration of a horn antenna do not really make it possible to meet the construction objectives at low cost and compact, suitable for consumer applications.

There is therefore a need to further improve the integration of antennascomets, intended for wireless communications, low consumption and high or very high speed, in particular for short-range communications, in particular to facilitate their construction, to reduce them. their costs and miniaturize them even more.

The object of the invention is to meet this need at least in part.

Statement of the invention

To do this, the invention relates to a wireless communication device, intended for communications in the millimeter frequency bands, comprising:

- a printed circuit (PCB) comprising a support of dielectric material and electrically conductive tracks separated by the dielectric support;

- at least one horn antenna, comprising:

• a straight waveguide, preferably of rectangular section, extended by a radiating opening of generally frustoconical shape or in truncated pyramid, the end of the radiating opening having two planes of symmetry perpendicular to each other, • two ribs s' extending opposite one another in one of the planes of symmetry, over at least part of the length of the waveguide and of the radiating opening, • one or more peripheral zones at least around the wave, forming one or more fixing flanges.

According to the invention, the horn antenna is a surface-mounted component (CMS) via the flange (s) supported by the PCB support and fixed on the latter, and the horn antenna is arranged with the waveguide and the radiating opening on either side of the PCB support and with each rib in direct contact or close to a PCB track, so as to allow direct connection or coupling capacitive between them.

Advantageously, the horn antenna is molded in one piece.

Thus, the invention essentially consists in defining a horn antenna whose structure allows it to be produced by integral molding of a usual material, in particular a metallized plastic or a zinc-based alloy, while being small in size. Its rear shape with a recess at the level of the rectangular part of the waveguide as well as its fixing flanges, allow it to be mounted like a usual surface-mounted component (CMS) vertically from the PCB and makes it perfectly compatible. with the related classical pick-and-place processes.

Having ribs makes it possible to reduce the dimensions of the radiating opening (horn) without having to install an additional dielectric element, to generate both types of horizontal and vertical polarizations, and to increase the purity of polarization. The shape of the ribs can be easily optimized as desired to obtain the best possible performance for transmission of HF (Hyper Frequency) signals.

On this subject, the inventors made first simulations which clearly show that at frequencies centered around 60GHz, the signal losses compared to a design of horn antenna without rib, which requires the implantation of a dielectric element solid, are quite negligible.

The SMD mounting of the horn antenna also makes it possible to have a very small overall height since the radiating opening can be centered on either side of the plane of the PCB support.

According to an alternative embodiment, the horn antenna, known as vertical polarization, has ribs arranged in the plane of symmetry of the end of its radiating opening which is perpendicular to the plane of the PCB.

According to an alternative, the horn antenna, known as horizontally polarized, has ribs arranged in the plane of symmetry of the end of its radiating opening which is perpendicular to the plane of the PCB.

According to an advantageous embodiment, the PCB comprises at least one notch, of complementary shapes with at least part of the radiating opening from its small base, in which the radiating opening is embedded at least in part, the guide straight wave surrounding in the extension of the bottom of the notch at least one conductive track on the face of the PCB on which the horn antenna is mounted. Here we get an installation of the horn antenna which makes the device even less bulky.

Advantageously, the horn antenna is adapted to radiate in the plane of the PCB.

According to an advantageous embodiment, the waveguide of each horn antenna has a step, so as to give it an asymmetry.

According to this mode, the horn antenna can advantageously be centered on the plane of the support of the PCB, so that its height (H), defined by the height of the radiating opening, is substantially distributed for half (H / 2) of on either side of said support plane.

Each horn antenna is preferably fixed to the PCB support by soldering using a reflow or wave technique.

According to another advantageous embodiment, the device comprises at least one alternation of two horn antennas arranged side by side, one of which is said to have vertical polarization and has its ribs arranged in the plane of symmetry of the end of its opening radiating which is perpendicular to the plane of the PCB support, and the other called horizontally polarized has its ribs arranged in the plane of symmetry which is perpendicular to the plane of the PCB support.

According to a first variant, one of the ribs of the vertically polarized horn antenna is in direct contact with a printed track while the other of the ribs is at a distance from the printed track.

In a second variant, the two ribs of the horn antenna with horizontal polarization being in direct contact with the two printed tracks.

The subject of the invention is also a method for producing a wireless communication device, comprising the following steps:

a / provision of a reference design of a printed circuit (PCB) comprising a support of dielectric material and electrically conductive tracks separated by the dielectric support;

b / production by integral molding of at least one horn antenna, comprising:

• a straight waveguide of rectangular section extended by a radiating opening of generally frustoconical shape or in truncated pyramid, the end of the radiating opening having two planes of symmetry perpendicular to each other, • two ribs extending opposite l 'from each other in one of the planes of symmetry, over at least part of the length of the waveguide and the radiating opening, • one or more peripheral zones at least around the waveguide, forming a or fixing flanges;

c / automatic installation of the horn antenna molded in one piece on the PCB support according to a technique called "pick and place", so as to have with the flange (s) supported by the support of the PCB and fixed on the latter, and the horn antenna arranged with the waveguide and the radiating opening on either side of the PCB support and with each rib in direct contact or near a PCB track , so as to allow respectively direct or capacitive coupling between them;

d / reflow or wave soldering of the horn antenna.

Advantageously, step d / is carried out simultaneously with other components mounted on the surface of the PCB.

The invention also relates to a wireless communication device, intended for communications in the millimeter frequency bands, comprising at least two wireless communication devices described above, each comprising a number of n identical alternations of two horn antennas, both devices being arranged opposite one another over a short distance, of the order of 1 cm.

Finally, the invention relates to the use of the wireless communication device as described above, for transmitting and / or receiving a number of n + 1 data streams in parallel at a frequency around 60 GHz.

The advantages of the invention are numerous, among which we can cite:

- low-cost construction on standard printed circuits and small footprint of the horn antenna device according to the invention, which makes it perfectly suitable for general public applications;

- perfect accounting with any pick-and-place process;

- easy integration into communicating electronic objects;

- obtaining a high-performance, perfectly reproducible solution for high speed, short distance, at a frequency of 60GHz from a plurality of alternately and vertically polarized horn antennas adjacent to horizontally polarized horn antennas;

- radiation in the plane of the PCB.

detailed description

The invention will be better understood on reading the detailed description which follows of nonlimiting examples of implementation thereof and on examining the appended figures among which:

Figure 1 is a perspective view from the front of an example of wireless communication device according to the invention with an alternation of two adjacent horn antennas respectively vertical and horizontal polarization mounted in CMS on a PCB;

- Figure 2 is a perspective view of an advantageous embodiment of PCB according to the invention;

- Figure 3 is a perspective view from the front of a horn antenna molded in one piece with ribs for vertical polarization according to the invention;

- Figure 4 is a rear perspective view of the horn antenna according to Figure 3;

- Figure 5 is a perspective view from the front of a horn antenna molded in one piece with ribs for horizontal polarization according to the invention;

- Figure 6 is a rear perspective view of the horn antenna according to Figure 5;

Figure 7 is a rear perspective view of a wireless communication device according to Figure 1;

Figure 8 is a top view of a wireless communication device according to Figure 1;

Figure 9 is a side view of a wireless communication device according to Figure 1;

Figure 10 is a front view from the front of a wireless communication device according to Figure 1;

Figure 11 is a front view from the rear of a wireless communication device according to Figure 1.

Throughout the present application, the terms “front”, “rear”, “upper” and “lower” are to be considered with reference to a device 1 according to the invention in an operating configuration in which the PCB support is horizontal and the radiating opening (horn) of the antenna widens from back to front.

There is shown in Figures 1 and 7 to 11, a wireless communication device 1, intended to ensure transmission / reception of signals in the millimeter frequency bands, and more particularly at 60GHz.

This device 1 firstly comprises a printed circuit PCB 2 with a dielectric support 20 with two plane faces 21, 22 parallel.

Two electrically conductive tracks 23, 24, conventionally made of copper, are produced on the upper face 21 of the support 20.

As can be seen in FIG. 2, the support 20 of the PCB is advantageously provided with metal zones 25 around the end of each of the tracks 23, 24 and two notches 26, 27 produced on an edge of the support 20.

In the example illustrated, these notches 26, 27 are in the general shape of an isosceles trapezoid. The bottom 28, 29 of these notches is arranged near the end of each of the tracks 23, 24.

As shown in Figures 1 and 7 to 11, the support 20 of the PCB supports alternating two horn antennas 3, 4, each molded in one piece, which are distinguished by the inner ribs 32, 33; 42, 43 which they comprise, as explained below.

The horn antennas 3, 4 according to the invention can advantageously be produced by injection molding of a metallized plastic or even of a metallic alloy.

As shown in FIGS. 3 to 6, each antenna 3, 4 comprises a straight wave guide 30, 40 of rectangular section extended by a radiating opening 31, 41 or horn in the shape of a truncated pyramid. The end of each horn 31, 41 has two planes of symmetry PI, P2 perpendicular to each other.

However, each straight waveguide 30, 40 has an asymmetry due to a recess 35, 45 on its lower part. This step 35, 45 allows vertical placement of each horn antenna on the support 20 of the PCB, advantageously compatible with a “pick & place” type mounting process.

Two ribs 32, 33 or 42, 43 extend opposite one another in one of the planes of symmetry PI, P2, over at least part of the length of the waveguide 30, 40 and the horn 31.41.

Each antenna 3, 4 finally comprises peripheral zones 34, 44 around the waveguide 30, 40 and around a part of the horn 31,41. These peripheral zones 34, 44 form flanges for fixing or holding each horn antenna 3, 4 mounted as a component on the surface CMS.

More specifically, the flanges 34, 44 are in planar support and supported by the support 20 while being fixed by brazing on the metal zones 25. In fact, during placement by pick & place, the recess 35, 45 can come in below the support 20 of the PCB, and the flanges 34, 44 come into abutment plane against the upper face 21 of the support 20.

Each horn antenna 3, 4 is embedded at least over part of the length of the horn 31, 41 in one of the notches 26, 27 of the support 20 of the PCB.

Each horn antenna 3, 4 is arranged with the waveguide 30, 40 and the horn on either side of the support 20 of the PCB.

Preferably, in order to further reduce the overall height, the horn antenna is centered on the plane of the support 20 of the PCB so that its height H, defined by the height of the horn 31, 41, is substantially distributed for half H / 2 on either side of the plane of the support 20 of the PCB.

In other words, one of the PI symmetry planes of each antenna is almost coincident with the plane of the support 20 of the PCB.

In other words again, to the thickness of the support close, half H / 2 of the height of the horn 31, 41 protrudes above the upper face 21 of the support 20 on which the antenna is mounted and the other half protrudes below the underside 22 of the support 20.

To ensure the transmission of the HF signals in the millimeter bands from or to the printed circuit, it is necessary to carry out either direct or capacitive coupling in the air between the ribs 32, 33; 42, 43 and the conductive tracks 23, 24 of the PCB.

To do this, each rib is in direct contact with or near a PCB track. In the examples illustrated, the ribs 33, 42 and 43 of the antennas are in direct contact with a track 23, 24 and 25 respectively.

In the alternation of the two horn antennas 3, 4 adjacent to the same device 1, the ribs 32, 33 of one are orthogonal to the plane of the support 20 of the PCB while the ribs 42, 43 of the adjacent one are arranged in the plane of the support 20 of the PCB.

The device 1 according to the invention which has just been described makes it possible to maintain a high or even very high bit rate, over a short distance of transmission of signals in transmission or reception at 60 GHz, by virtue of the juxtaposition of vertically polarized horn antennas 3 and horizontal 4.

Thus, each antenna is isolated from the adjacent antenna and thus allows the transmission of a data stream very distinct from the adjacent one.

In addition, the size of the device 1 is reduced, on the one hand because of the very small dimensions which it is possible to achieve for a horn antenna by an embodiment by molding, and on the other hand by the centering of the antenna, the horn of which is distributed half above the plane of the PCB support and the other half below the latter. As an example, it is entirely possible to make an integral molded horn antenna with dimensions L * H * 1 of the order of 7 x 3.5 x 7 mm.

The invention is not limited to the examples which have just been described; in particular, it is possible to combine characteristics of the examples illustrated within 5 variants not illustrated.

Other variants and improvements can be envisaged without departing from the scope of the invention.

For example, if all the horns (radiating openings) illustrated 30, 40 of the antennas 3, 4 are of truncated pyramidal shape, the invention can also be applied to horns of section in truncated cone.

Furthermore, if in the examples illustrated, the support 20 of the PCB is advantageously provided with notches 26, 27 of shapes complementary to those of the horn 31, 41 of the antennas 3, 4 in order to optimize the space requirement by embedding on at least a portion of the horns can be provided with a lesser or greater embedding.

In the latter case, the opening face of the horn by which the transmission / reception of the signals is made is recessed inside the PCB support.

Claims (17)

1. Wireless communication device (1), intended for communications in the millimeter frequency bands, comprising: - a printed circuit (PCB) (2) comprising a support (20) made of dielectric material and electrically conductive tracks (23, 24) separated by the dielectric support; - at least one horn antenna (3, 4), comprising: • a straight waveguide (30, 40), preferably of rectangular section, extended by a radiating opening (31, 41), the end of the radiating opening having two planes of symmetry perpendicular to each other, • two ribs (32, 33; 42, 43) extending opposite one another in one of the planes of symmetry, over at least part of the length of the waveguide and of the radiating opening, • a or peripheral zones (34, 44) at least around the waveguide, forming one or more fixing flanges, device in which the horn antenna is a surface-mounted component (CMS) by means of the flange (s) supported by the PCB and fixed on the latter, and the horn antenna is arranged with the waveguide and the radiating opening on either side of the PCB and with each rib in direct contact or near a PCB track, so as to allow direct bonding or capacitive coupling between re them. 2. Device according to claim 1, the end of the radiating opening having a square, rectangular, circular, or elliptical section. 3. Device according to claim 1 or 2, the horn antenna being molded in one piece. 4. Device according to one of the preceding claims, the horn antenna, said to be vertically polarized, having ribs (32, 33) arranged in the plane of symmetry (P2) which is perpendicular to the plane of the PCB (2). 5. Device according to one of the preceding claims, the horn antenna, called horizontally polarized, having ribs (32, 33) arranged in the plane of symmetry (P2) which is perpendicular to the plane of the PCB (2). 6. Wireless communication device (1) according to one of the preceding claims, the PCB comprising at least one notch (26, 27), of complementary shapes with at least part of the radiating opening from its small base, in which the radiating opening is embedded at least in part, the right waveguide surrounding in the extension of the bottom (28, 29) of the notch at least one conductive track on the face of the PCB on which the horn antenna is climb. 7. Wireless communication device according to one of the preceding claims, the horn antenna being adapted to radiate in the plane of the PCB. 8. Wireless communication device (1) according to one of the preceding claims, the waveguide of each horn antenna (3, 4) having a step (35, 45) so as to give it an asymmetry. 9. Wireless communication device (1) according to claim 8, the horn antenna being centered on the plane of the support of the PCB, so that its height (H), defined by the height of the radiating opening, is substantially distributed for half (H / 2) on either side of said support plane. 10. Wireless communication device (1) according to one of the preceding claims, each horn antenna being fixed to the support of the PCB by soldering using a reflow or wave technique. 11. Wireless communication device (1) according to one of the preceding claims, comprising at least one alternation of two horn antennas (3,4) arranged side by side, one of which (3) is said to be vertically polarized has its ribs (32, 33) arranged in the plane of symmetry (P2) of the end of its radiating opening which is perpendicular to the plane of the support (20) of the PCB (2), and the other (3) said to horizontal polarization has its ribs (32, 33) arranged in the plane of symmetry (P2) which is perpendicular to the plane of the support (20) of the PCB (2). 12. Wireless communication device (1) according to claim 4 or 11, one of the ribs of the vertically polarized horn antenna being in direct contact with a printed track while the other of the ribs is at a distance from the printed track . 13. Wireless communication device (1) according to claim 5 or 11, the two ribs of the horn antenna with horizontal polarization being in direct contact with the two printed tracks. 14. Method for producing a wireless communication device, comprising the following steps: a / provision of a reference design of a printed circuit (PCB) comprising a support of dielectric material and electrically conductive tracks separated by the dielectric support; b / production by integral molding of at least one horn antenna comprising: • a straight waveguide of rectangular section extended by a radiating opening, the end of the radiating opening having two planes of symmetry perpendicular to each other, • two ribs extending opposite one another in a planes of symmetry, over at least part of the length of the waveguide and of the radiating opening, • one or more peripheral zones at least around the waveguide, forming one or more fixing flanges; c / automatic installation of the horn antenna molded in one piece on the PCB support according to a technique called "pick and place", so as to have with the flange (s) supported by the support of the PCB and fixed on the latter, and the horn antenna arranged with the waveguide and the radiating opening on either side of the PCB support and with each rib in direct contact or near a PCB track , so as to allow respectively direct or capacitive coupling between them; d / reflow or wave soldering of the horn antenna. 15. The production method according to claim 13, step d / being carried out simultaneously with other surface-mounted components on the PCB. 16. Wireless communication device, intended for communications in the millimeter frequency bands, comprising at least two wireless communication devices according to one of claims 10 to 12, each comprising a number of n identical alternations of two horn antennas , the two devices being arranged opposite one another over a short distance, typically of the order of 1 cm. 17. Use of the wireless communication device according to claim 15, for transmitting and / or receiving a number of n + 1 data streams in parallel at a frequency of about 60 GHz.