PCB antenna, electronic circuit and electronic equipment part provided with such PCB antenna

Abstract

An antenna includes a fastener body carrying a conductive circuit having at least one signal input section and a radiating section, the fastener body including two positioning parts defining a channel between the two positioning parts having a size suitable for receiving an edge of a PCB carrier, the input section being carried by one of the positioning parts to extend facing a side of the carrier, and the body including means for clamping the carrier against one of the positioning parts. An electronic circuit and an electronic equipment part including the antenna.

Description

[0001] The present invention relates to the field of radio frequency (RF) transmissions. Prior art

[0002] Known electronic circuits comprise a support board carrying electronic components connected to conductive tracks printed on the support board.

[0003] When the electronic circuit is dedicated to radio frequency transmission of signals, one of the tracks is connected to an antenna.

[0004] The antenna can have various forms. There are antennas formed directly from conductive tracks extending on a support plate. However, this increases the size of the support plate. There are also separate antennas connected to the conductive tracks of the support plate via connectors and cables. This complicates the manufacture of the electronic circuit and makes it necessary to provide means for fixing the antenna in the housing containing the electronic circuit.

[0005] Purpose of the Invention

[0006] It is an object of the present invention to provide means for simplifying the manufacture of an electronic circuit with an antenna without increasing the size of the electronic circuit. Summary of the invention

[0007] To this end, the present invention provides an antenna, which includes a fastener body carrying a conductive circuit, the conductive circuit having at least one signal input section and a radiation section, the fastener body including two positioning parts, the two positioning parts defining a channel with a size suitable for receiving the edge of a printed circuit support board, the input section being carried by one of the positioning parts to extend toward a side of the support board, and the body including a clamping device for clamping the support board against at least one of the positioning parts.

[0008] Thereby, the antenna is arranged to be fixed on the edge of the printed circuit board, thereby limiting the footprint of the antenna on the printed circuit board and enabling connection to the printed circuit to be provided in a simple manner by means of an input section extending towards one side of the board.

[0009] Advantageously, the clamping means comprises an elastically deformable zone connecting at least one of the detents to the remainder of the body to urge said detent into a position in which the width of the channel is less than the thickness of the support plate.

[0010] This fastening technique is particularly simple since the clamping force is solely a result of the elasticity of the fastener body without having to resort to any external clamping means.

[0011] In a first embodiment, the input section is positioned to establish an electromagnetic coupling with the conductive track of the support plate.

[0012] This connection technique is easy to manufacture and quite robust.

[0013] In the second embodiment, the antenna circuit has two contacts, each of which is mounted in one of the positioning portions so that one end of the contact elastically protrudes from the positioning portion and faces the other positioning portion to form two input sections.

[0014] Advantageously, the radiation portion is concave-convex.

[0015] This improves the transmit and receive performance of the antenna.

[0016] The present invention also provides an electronic circuit, comprising:

[0017] a support plate carrying electronic components connected to conductive tracks extending on at least one first face of the support plate,

[0018] An antenna comprising a fastener body carrying a conductive circuit having at least one signal input section and a radiating section, the fastener body comprising two positioning portions defining a channel between the two positioning portions in which an edge of a support plate is clamped, the input section being carried by one of the positioning portions to extend toward a side of the support plate.

[0019] Finally, the invention provides an electronic device comprising a housing for receiving such an electronic circuit, wherein the antenna also extends within the housing near an outer wall of the housing to have a radiation field outside the outer wall of the housing.

[0020] Other characteristics and advantages of the invention will emerge on reading the following description of a particular, non-limiting embodiment of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] With reference to the accompanying drawings, in which:

[0022] · Figure 1 is a partial diagrammatic view from the perspective of electronic equipment in a first embodiment of the present invention;

[0023] · Figure 2 The second embodiment of the present invention is related to the electronic equipment shown in FIG. Figure 1 Similar view.

[0024] Detailed description of the invention

[0025] With reference to the accompanying drawings, the invention is described herein as applied to electronic equipment including a housing enclosing an electronic circuit.

[0026] The electronic circuit comprises:

[0027] a support plate 10 (also called a printed circuit board (PCB)) having a first face 10.1 and a second face 10.2,

[0028] conductive tracks 11 extending on the first face 10.1 and on the second face 10.2 of the support plate 10 to form a printed circuit,

[0029] electronic components carried by the support plate 10 and electrically connected to the conductive tracks 11,

[0030] • An antenna given the overall reference numeral 1 .

[0031] The antenna 1 comprises a fastener body 2 made of an electrically insulating material and carrying an electrically conductive circuit given the general reference numeral 3. The fastener body 2 has two detents 2.1 and 2.2 defining between them a channel defined by parallel flanks spaced a distance sufficient to receive the edge of the support plate 10. In this example, the fastener body 2 has a thickness of 5.25 millimeters (mm) and is made of acrylonitrile butadiene styrene (ABS) having a dielectric constant εr of about 2.8.

[0032] The fastener body 2 has a clamping device for clamping the support plate 10 against at least one of the positioning parts 2.1, 2.2. The clamping device includes an elastically deformable area that connects the positioning parts 2.1 and 2.1 to the rest of the body to force the positioning parts to be in a position where the width of the channel is less than the thickness of the support plate 10, so that the edge of the support plate 10 is clamped in the channel by the positioning parts 2.1 and 2.2 being elastically pinched on the edge of the support plate 10.

[0033] The circuit 3 comprises at least one signal input section and a radiating section 5. The radiating section 5 is concave-convex, ie it extends on a non-planar surface and, more precisely in this example, is curved around a single axis.

[0034] The input section is carried by the positioning portion 2 . 1 and extends toward the surface 10 . 1 of the support plate 10 .

[0035] The circuit 3 is arranged as a single band circuit or as a multi-band circuit. As an example, the circuit 3 operates at a frequency of 2.45 Gigahertz (GHz) for use in the 2.4 GHz to 2.5 GHz frequency band for local area networks conforming to the IEEE 802.11 standard.

[0036] Preferably, the circuit 3 has an impedance of 50 Ohms and is arranged to exhibit a return loss greater than 10 decibels (dB) and an efficiency of at least 70% (ie 70% of the energy consumed is radiated).

[0037] The antenna 1 extends in the housing near an outer wall 100 of the housing so as to have a radiation field outside the outer wall 100 of the housing.

[0038] exist Figure 1 In the embodiment of the present invention, the input section (given reference numeral 4) is positioned to establish an electromagnetic coupling with the conductive track 12 of the support plate 10. For this purpose, when the fastener body 12 is correctly positioned at the edge of the support plate 10, the input section 4 extends parallel to the track 12 and faces the track 12. Preferably, the input section 4 is spaced apart from the track 12 by a distance in the range 1 mm to 5 mm.

[0039] The conductive track 12 has a width of 0.5 mm and has a main section of length l1 of 7.50 mm and two end sections perpendicular to the main section, each of which has a length l2 of 3.65 mm. The input section 4 has the same length and the same width as the main section of the conductive track 12. The input section 4 has a first end connected to an artificial ground 8 of length l3 of 6.25 mm via an intermediate section of length l5 of 2.5 mm and a second end connected to the radiating section 5 via an intermediate section of length l4 of 8.05 mm. The radiating section 5 is substantially U-shaped, with one branch connected at its free end to the intermediate section of length l4 and the other branch being free. These branches have a length l6 of 8.94 mm. These values ​​are given only as an example.

[0040] It should be observed that in this example, the fastener body 2 is generally U-shaped, with two outer surfaces being planes connected to each other by a concave curved surface. The flat outer surfaces are parallel to the flanks of the channel. The radiating section 5 extends on a portion of the flat outer surface fixed to the positioning portion 2.1 and on the curved outer surface.

[0041] exist Figure 2 In the embodiment of FIG. 1 , the circuit 11 has two electrically conductive areas 13 and 14 extending on the face 10 . 1 of the support plate 10 .

[0042] The circuit 3 has two contacts 6 and 7 mounted in the positioning portion 2.1, one end of each contact protruding elastically from said positioning portion 2.1 into the channel to be elastically pressed against a respective one of the conductive areas 13 and 14. The contacts 6 and 7 thus form two input sections of the circuit 3.

[0043] It should be observed that in this example the fastener body 2 is generally U-shaped, having a cylindrical outer surface of circular cross-section. The radiating section 5 extends over said outer surface.

[0044] Of course, the invention is not limited to the embodiments described but covers any variant coming within the scope of the invention as defined by the claims.

[0045] In particular, the fastener body may be molded as one piece or obtained by assembling multiple pieces together.

[0046] The fastener body may have a shape other than that described and may, for example, have the shape of a parallelepiped.

[0047] The clamping means may comprise an element which is screwed into one of the detents of the fastener body to press the support plate against the other detent.

[0048] The circuitry of the antenna may be deposited on the fastener body and then optionally covered with a varnish, or may be embedded in the material of the fastener body.

[0049] The body may be made of a plastic material such as ABS or some other material such as ceramic.

[0050] The electronic circuit 3 may be arranged to operate in other frequency bands, for example in the Long Term Evolution (LTE) or Global System for Mobile (GSM) telephony bands.

Claims

1. An antenna (1), comprising a fastener body (2) made of an electrically insulating material and carrying a conductive circuit (3), the conductive circuit (3) having at least one signal input section (4) and a radiating section (5), the fastener body comprising two positioning parts (2.1, 2.2), between which a channel having a size suitable for receiving an edge of a printed circuit support board (10) is defined, the input section (4) being carried by one of the positioning parts (2.1) to extend facing the surface (10.1) of the support board, characterized in that The body comprises clamping means for clamping the support plate against at least one of the positioning portions, the input section (4) being positioned to establish an electromagnetic coupling with the conductive track (12) of the support plate (10).

2. The antenna according to claim 1, characterized in that The clamping device comprises an elastically deformable area which connects at least one of the positioning parts (2.1, 2.2) to the rest of the fastener body (2) to force the positioning part into a position where the width of the channel is less than the thickness of the support plate (10).

3. An antenna as claimed in any preceding claim, characterised in that The radiation section (5) is concave-convex.

4. The antenna according to claim 3, characterized in that The radiating section (5) is curved.

5. An electronic circuit comprising: · a support plate (10) carrying electronic components connected to conductive tracks extending on at least one first face (10.1, 10.2) of the support plate, · An antenna (1) comprises a fastener body (2) carrying a conductive circuit (3), the conductive circuit (3) having at least one signal input section (4) and a radiation section (5), the fastener body comprising two positioning parts (2.1, 2.2), between which a channel is defined in which the edge of the support plate is clamped, characterized in that the input section is carried by one of the positioning parts (2.1) to extend facing a surface (10.1) of the support plate, and the support plate (10) is provided with at least one conductive track extending in the channel to establish electromagnetic coupling between the input section (4) and the conductive track of the support plate (10).

6. The circuit according to claim 5, characterized in that The positioning parts (2.1, 2.2) elastically pinch the edge of the support plate (10).

7. An electronic device comprising a housing for receiving the electronic circuit as claimed in any one of claims 5 to 6, wherein the antenna (1) further extends in the housing near an outer wall (100) of the housing to have a radiation field outside the outer wall of the housing.

Images