AN ANTENNA DEVICE ARRANGED TO BE CONNECTEDTO A PIECE OF ELECTRIC EQUIPMENT
FIELD OF INVENTION
The present invention relates generally to an antenna device adapted for connection to a radio communication device such as a mobile phone.
BACKGROUND
Many prior art antennas for radio communication devices such as mobile phones are attached to the phone housing by means of a screw or a snap-in connection which provides fastening as well as electrical connection. However, a problem of these prior art antennas is the inflexibility in the manufacturing of antennas. The connecting means is adapted for each application with corresponding inflexibility of manufacturing.
The European patent application no. 98660007.0 discloses a method of connecting an antenna wherein connecting means comprise a first and a second contact pin forming two opposed contacts pins. The connecting means are adapted for connecting an external antenna to e.g. a PCMCIA card.
The US patent 5,929,813 (Eggleston) discloses an antenna device wherein an antenna element is connected to electronic circuits of a mobile phone through an an- tenna connector provided as a separate part between the antenna element and the electronic circuits. The connection between the antenna element and the antenna connector is effected by means of two resilient terminals provided integral with the antenna element and wherein the two terminals exert pressure in opposite directions on the separate antenna connector. However,
this solution requires a very special shape of the antenna element, making it inconvenient for many applications .
SUMMARY OF THE INVENTION An object of the present invention is to provide an antenna device, which is easy to change and assemble.
Another object is to provide an antenna module comprising an antenna device.
The invention is based on the realization that the pro- vision of a separate resilient connector adapted to interconnect an antenna element and a printed circuit board provides a flexible solution to the connection of the antenna device to electric circuitry of a portable telecommunications device such as a mobile phone.
According to the invention there is provided an antenna device as defined in claim 1.
There is also provided an antenna module as defined in claim 11. A radio communication device comprising such an antenna device or antenna module as defined in claim 15 is also provided.
Further preferred embodiments are defined in the dependent claims.
The antenna device according to the invention is very flexible regarding the possible antenna patterns. Also, by providing a resilient connector arranged to make contact with connector portions of the antenna element, the antenna element is easy to replace. It is easy to handle and store the antenna device, especially when
the antenna body is made of a rigid and flat material, such as a laminate.
BRIEF DESCRIPTION OF DRAWINGS
The invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Fig. 1 is an overview of a frame of an antenna module according to the invention;
Fig. 2 is a view of the antenna module of Fig. 1 with an antenna PCB partly inserted into the frame;
Fig. 3 is a view of the antenna module with the antenna PCB fully inserted into the frame;
Fig. 4 is a view of the frame mounted to a telephone circuit card of a mobile phone;
Fig. 5 is a an overview of a second embodiment of an antenna module according to the invention;
Fig. 6 is a view of the antenna module of Fig. 5 in assembled condition;
Fig. 7 is an overview of a third embodiment of an antenna module according to the invention;
Fig. 8 is an end view of the antenna module of Fig. 7;
Fig. 9 is a view of the underside of the antenna module of Fig. 7;
Fig. 10 is a detail view of a resilient connector comprised in the antenna module shown in Fig. 7; and
Fig. 11 is a sectional view of the antenna module shown in Fig. 8 taken along the lines XI-XI.
DETAILED DESCRIPTION OF THE INVENTION
In the following a preferred embodiment of the inven- tion will be described. In Fig. 1 there is shown a frame, generally designated 20, for mounting of a flat rectangular printed circuit board (PCB) 10 comprising a laminate with an antenna pattern 12 thereon, see Fig. 2. The pattern 12 constitutes an antenna element oper- able to transmit and/or receive RF signals and is provided on the laminate by means of conventional technology such as etching or printing. In the preferred embodiment, the laminate is rigid, i.e., it is not prone to bending.
At one end portion of the PCB 10 there is provided an edge connector in the form of two conducting parts 14a, 14b in electrical contact with the antenna pattern 12, the function of which conducting parts will be explained below.
The PCB 10 is adapted to be mounted to a flat surface of the "pool table" shaped frame 20. The frame 20 supports two generally U-shaped spring leaf connectors 22a, 22b adapted for co-operation with the edge connector 14a, 14b. The connectors 22a, 22b are riveted to a respective contact pin 24a, 24b, see Fig. 1. The contact pins connect to an underlying PCB comprising electric circuitry, etc. of a mobile phone, which will be explained later with reference to Fig. 4.
During mounting of the PCB 10 it is simply slid onto the frame 20, see Fig. 2, and into contact with the
spring leaf connectors 22a, 22b. The frame is provided with a border 26a, 26b along the long sides of its upper surface. The function of the borders is to guide the PCB 10 and to keep it in position after mounting. To that end two protrusions 28a, 28b are provided close to an end portion thereof, see Fig. 1, preventing the accidental removal of the PCB 10. The PCB 10 is also held in place by means of the force exerted by the connectors 22a, 22b.
The upper surface of the frame 20 is also provided with a longitudinal groove 30, the function of which is twofold. Firstly, it facilitates mounting of the PCB 10 onto the frame 20. Secondly, in case electric components are mounted on the underside of the PCB 10, the groove provides a space for these components. Thus, the groove 30 can have any suitable width.
The assembled module comprising the PCB 10 and the frame 20 is shown in Fig. 3. It is there shown how the spring leaf connectors 22a, 22b are wrapped around the edge of the PCB 10 in the area of the edge connectors 14a, 14b, thus establishing contact there between. It is also shown how the protrusions 28a, 28b prevent the PCB 10 from sliding out of contact with the spring leaf connectors. During intentional removal of the PCB 10, it is simply lifted above the protrusions and pulled out of the frame 20.
In Fig. 4 the module is snap fitted to an underlying main printed circuit board 40 of a mobile phone and mounted directly above a shielding box 42. The legs of the frame end in a respective hook 32a, 32b, gripping around the edges of the underlying board. The spring
leaf connectors then contacts the underlying board by means of the contact pins 24a, 24b.
The antenna device according to the invention provides several advantages. Firstly, the antenna pattern is very easy to provide on the laminate 10, being a conventional, rectangular board. It also enables easy changes of the antenna pattern for a piece of electric equipment during development work or later. During e.g. service, the PCB 10 is simply exchanged for another with a different antenna pattern 12. It is also easy to manufacture and assemble.
A second embodiment of an antenna device and module will now be described with reference to figs. 5 and 6. The module comprises a PCB 110 with an antenna pattern 112 connected to contact surfaces 114a, 114b. These contact surfaces are connected to corresponding surfaces (not shown) on the under side of the PCB 110 by means of e.g. through holes (not shown). Antenna patterns can thus be provided on one or both sides of the PCB. The PCB is attached to a frame 120 by means of a double-sided adhesive film 130.
The frame comprises two contact pins 124a, 124b provided with resilient spring connectors 122a, 122b. After assembly of the PCB 110 and the frame 120, the connectors 122a, 122b rest on a respective contact area (not shown) on the under side of the PCB 110, thereby providing electrical contact between the antenna pattern (s) of the PCB 110 and the frame 120. The contact pins 124a, 124b can then be brought into electri- cal contact with e.g. an underlying PCB (not shown) or the like.
A third embodiment will now be described with reference to Figs. 7-11. In Fig. 7 is shown a rectangular "pool table" shaped frame 220, having four depending legs 222 at the corners thereof. There are also two depending legs 224 at the short sides of the frame 220 provided with a respective hook-shaped end portion 225 arranged for snap-fitting to an underlying PCB 240 (shown in figure 11) . The frame also comprises a depending portion 226 adapted for supporting connector elements 230 to be described in more detail below with reference to Fig. 10. Thus, the support portion 226 is provided with two holes 228 arranged for receiving a contact portion of a respective connector element 230, see Fig. 11.
On the upper surface of the frame 220 there is provided a flexible film 210 having a conductive pattern forming an antenna element 212. The antenna element also comprises two tongue-shaped connector parts 214 being wrapped around a side edge of the upper surface of the frame 220, see Figs. 8 and 11. Thus, the connector parts or tongues 214 of the flexible film are pushed into the above-mentioned holes 228 in the support portion 226.
The connector element 230 is shown in detail in Fig. 10. It is made of a strip of conductive sheet metal bent to the desired shape and comprises an upper generally straight portion 232 and a lower curved portion 234. The upper portion 232 is arranged to be inserted into one of the holes 228 in the support portion 226 of the frame 220 while the lower portion 234 is adapted to rest on an underlying PCB 240, see
Fig. 11, and to exert a force on a contact pad thereon (not shown) .
The upper portion 232 of the connector element 230 is provided with a protruding spring portion 236 created by means of a punch process, for example. The spring portion 236 is arranged to exert a pressure on the connector part 214 of the flexible film 210 when the upper portion 232 of the connector element 230 has been inserted into one of the holes 228. The exerted pressure ensures a firm and well-defined contact between the connector part 214 and the contact element 230.
Preferred embodiments of an antenna device according to the invention have been described. However, it is realized that these can be varied within the scope of the invention as defined in the appended claims. Thus, in the figures, exemplary antenna patterns have been shown. They can of course have any suitable shape, depending on the desired characteristics.
In the described embodiments, the connector of the PCB 10, 110, 210 comprises two parts. There could of course be any suitable number of contact points between the PCB 10, 110, 210 and the frame 20, 120, 220. Also, the width of the contact points could be adapted to specific applications.
It is also possible to provide an antenna pattern on both sides of the PCB 10 of the first embodiment. In that case, there could be provided separate spring leaf connectors for the lower antenna pattern.
The spring leaf connectors of the two embodiments described with reference to Figs. 1-6 have been shown riveted to contact pins contacting an underlying PCB such as a telephone circuit card. It is realized that
the spring leaf connectors could be connected to the electric circuitry in any suitable way such as by being soldered directly thereto.
Also, it is very easy to mount electric components on the PCB 10, 110, 210 such as discrete electric components or components integrated into the antenna pattern.
The frame 20 has been shown provided with hooks for snap fitting. The mounting of the frame can also be by means of e.g. screw fastening, gluing etc.
Although the frame connectors have been shown as spring leaf connectors, any suitable connector can be used.
The PCBs 10, 110, 210 have been shown with an essentially rectangular shape. They can have any suitable shape such as tapered etc.