MXPA99005184A - Dual-band antenna coupler for a portable radiotelephone - Google Patents

Abstract

A dual-band antenna coupler (100) for use in an adapter for portable radiotelephone (200). A plurality of curved bands of metal (204a-c) are positioned on a ground plane (102), with at least two of the plurality of curved bands (204a, 204b) of metal being electrically isolated from the ground plane (102) so as to couple radio frequency (RF) signals to and from the antenna (204) of the portable radiotelephone (200). The isolated curved bands (204a, 204b) of metal couple RF signals between the antenna (204) of the portable radiotelephone and first and second matching circuits (602, 604) designed to match the portable radiotelephone antenna (204) at each of the respective frequency bands. A selector switch (606) coupled to the output of the matching circuits (602, 604) selects the appropriate matching circuit output for connection to an external antenna (304). The adapter also includes at least one ground pin (206a-c) mounted on the ground plane (102). When the portable radiotelephone (200) is interfaced with the antenna coupler (100), the ground pin (206a-c) makes electrical contact with a ground reference connection on the portable radiotelephone (202a, 202b, 208).

Description

DOUBLE BAND ANTENNA COUPLER FOR A PORTABLE RADIO-TELEPHONE BACKGROUND OF THE INVENTION I. Field of the Invention The present invention relates generally to antenna couplers. More particularly, the present invention is directed to an improved and novel antenna coupler for a portable radiotelephone.

II. Description of the Related Art In the field of cellular communications, portable radiotelephones are used to communicate with base stations over radio frequencies (RF).

Typically, these portable radiotelephones operate at relatively low energy levels to conserve battery power and increase talk time. However, when alternative energy means are available, such as a vehicle battery when driving, or a conventional electrical outlet, when in the interior, the user of the portable radiotelephone frequently employs special adapters to take advantage of the higher power supply. available energy For example, there are many vehicle adapters, which transform the electrical power generated by the vehicle to suitable levels to be used by the portable telephone, and also to couple the RF signals to, and the portable radiotelephone to be used with an auxiliary power generator. external and an antenna. Additionally, these adapters can include a hands-free kit that includes an auxiliary microphone and loudspeaker, allowing the user to take advantage of increased hands-free talk and transmission power, without sacrificing battery time, and still be able to transport the same portable radiotelephone with it when you leave your car.To couple the FR signal to, and the portable radiotelephone, a typical vehicular adapter uses an inductive coupler placed near the portable radiotelephone's antenna. This technique can result in a significant amount of energy loss of the FR signal, particularly when a FR return path, or insufficient grounding, is provided to the portable radiotelephone while it is in the adapter. Typical portable radiotelephone are encapsulated in a shield against electromagnetic interference To (EMI) to prevent the leakage of parasitic electromagnetic energy from the radiotelephone case, the prior art vehicle adapters have not been able to achieve a sufficient FR return path to the portable radiotelephone.

BRIEF DESCRIPTION OF THE INVENTION The present invention is incorporated in an antenna coupling device used to adapt a portable radiotelephone cable operating in two frequency bands. The antenna coupling device comprises a ground plane having a top surface with an antenna coupler mounted on the top surface. The antenna coupler couples the radio signals to, and the antenna of the communication device. The grounding plane also includes at least one grounding pin, capable of coming into contact with an externally accessible ground point on the radio communication device. An adaptation circuit coupled to the antenna coupler generates a predetermined impedance to adjust the coupler of the antenna to the antenna of the communication device to each of the first and second frequency bands. The grounding plane may also include first and second vertical portions in contact, mounted on the upper surface thereof. The first and second vertical portions in contact, are placed in a substantially orthogonal relationship with each other and with the upper surface of the ground plane. In a first embodiment, a plurality of curved metal bands are placed near the ground plane with the first of the curved bands being electrically isolated from the grounding plane, for coupling the radio signals a, and the antenna of the communication device, when the communication device is operating at a first of the two frequency bands. A second of the curved bands is also electrically isolated from the ground plane for coupling the radio signals a, and from the antenna of the communication device, when the communication device is operating with a second of the two frequency bands. A third of the curved bands is electrically coupled to the ground plane. The adaptation circuit may comprise first and second adaptation circuit portions, each of which has an input terminal for adapting the antenna of the communication device. The first portion of the adaptation circuit is used when the communication device is operating at the first frequency band and the second portion of the adaptation circuit operates when the communication device is operating is the second frequency band. The input terminal of the first portion of the adaptation circuit is coupled to the first curve band, while the second input terminal of the adaptation circuit portion is coupled to the second curve band. In a second embodiment, a coupling bolt makes direct contact with a radio frequency component of the communication device, such as the antenna of the communication device. In this mode, there is no need to couple the signal over the air using the curved bands. The output of the coupling pin can be connected to a single dual band adaptation circuit, designed to generate a predetermined impedance for adapting the antenna coupler to the antenna of the communication device to each of the first and second frequency bands. Alternatively, the coupling device may include a switching circuit coupled between the coupling bolt and the first and second portions of the matching circuit. The switching circuit couples the coupling bolt to the first portion of the adaptation circuit for the operation of the communication device in the first frequency band and couples the coupling bolt to the second adaptation circuit portion for operation of the device of communication in the second frequency band.

In a third further mode, a helical coupler surrounds at least a portion of the antenna of the communication device and couples the radio frequency signals over the air. The signals of the adaptation circuit or the portions of the adaptation circuit can optionally be connected to a booster amplifier and connected to an external antenna.

BRIEF DESCRIPTION OF THE DRAWINGS The features, objects and advantages of the present invention will become more apparent from the detailed description set forth below, when taken in conjunction with the drawings, in which similar reference characters identify all that corresponds and wherein: FIGURE 1A is an illustration of an exemplary radiotelephone, suitable for use with the present invention; FIGURE IB is an illustration of a first antenna coupler embodiment of the present invention that is interconnected with an exemplary portable radiotelephone; FIGURE 2A is an illustration of one embodiment of the coupling elements of the present invention; FIGURE 2B is an illustration of an alternative embodiment of the coupling elements of the present invention; FIGURE 3A is an illustration of a second embodiment of the antenna coupler of the present invention, which is interconnected with a direct connection to an exemplary portable radiotelephone antenna, shown in a partially cut-away view; FIGURE 3B is an illustration of a second embodiment of the coupling elements of the present invention, which are interconnected with a direct connection to an internal component of an exemplary portable radiotelephone; FIGURE 4A is an illustration of a third embodiment of the antenna coupler of the present invention, which is interconnected with an exemplary portable radiotelephone; and FIGURE 4B is an illustration of the helical coupler of the third embodiment of the present invention, which interconnects with an antenna of an exemplary portable radiotelephone; FIGURE 5A is an illustration of one embodiment of the dual band coupling elements of the present invention; FIGURE 5B is an illustration of an alternative embodiment of the dual-band coupling elements of the present invention; FIGURE 6 is a functional block diagram of a dual band adaptation circuit used with the antenna coupler of FIGURES 3A, 3B, 4A and 4B; FIGURE 7 is an alternative embodiment of the dual band adaptation circuit used with the antenna coupler of FIGURES 3A, 3B, 4A and 4B.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGURE IB, a first embodiment of the antenna coupler 100 of the present invention comprises a ground connection plane 102, in contact with the vertical portions of the ground connection plane 104 and 106, the coupling elements 204a, 204b, and 204c and the grounding bolts 206a, and 206b, and the optional grounding bolt 206s. Coupling elements 204a, 204b, and 204c are preferably constructed of vertically oriented, curved bands of conductive material, such as copper, steel, or the like. When the portable radiotelephone 200 is interconnected with the antenna coupler 100, the coupling elements 204a, 204b, and 204c receive the retracted helical antenna 204 of the portable radiotelephone 200 and couple the signals of FR a, and of the antenna 204. The elements Coupling 204a, 204b, and 204c are constructed and positioned in such a manner that when the portable radiotelephone 200 is interconnected with the antenna coupler 100, the coupling elements 204a, 204b, and 204c extend in a semicircular arrangement, each covering about a quarter of the circumference of the antenna 204. It should be noted that the antenna 204 may also be non-helical in construction, as is known in the art, such as a rod or ring antenna. It should also be noted that the portable radiotelephone 200 can, in general, be any type of mobile communication device, such as a cellular or PCS radiotelephone, or a wireless local circuit communication device. The coupling elements 204a, 204b, and 204c are mounted on a base of the coupler respective to the ground plane 102. In the preferred embodiment, the ground plane 102 is a printed two-sided wired board (PWB) . However, a single-sided PWB would also provide a suitable construction for the ground connection plane 102, or any large base covered with a layer of conductive material. The ground plane 102 provides an improved return path for the RF energy of the antenna 204 to a ground connection reference point within the portable radiotelephone 200. The vertical portions of the ground plane in contact 104 and 106, also serve to improve the return path of the RF energy of the antenna 204 to a ground connection of the radiotelephone 200. The vertical portion of the contacting ground plane 104 is placed in a substantially parallel arrangement with respect to to an upper surface 200a (see FIGURE IB) of the radiotelephone 200, when the radiotelephone is used with the antenna coupler 100. The vertical portion of the contacting ground plane 106 is placed in a substantially orthogonal position with respect to the vertical portion of the contact ground plane 104, thereby placing the vertical portion of the connection plane , ground contact 106 in a substantially parallel position with respect to a longitudinal axis of antenna 204 (see FIGURE IB). In order to couple the RF energy of the antenna 204, at least one of the coupling elements 204a, 204b and 204c is electrically insulated from the ground plane 102. The ground plane 102 also serves to electrically couple the pins of the antenna. ground connection 206a, 206b and (optionally) 206s to at least one of the coupling elements 204a, 204b and 204c. That is, each of the grounding bolts 206a-206c, the grounding plane 102, and at least one of the coupling elements 204a-204c share the electrical grounding potential. Therefore, a complete FR signal path can be provided to couple the RF signals to and from the antenna 204 by connecting the ground connection bolts 206a, 206b and (optionally) 206c to a suitable ground connection on a portable radiotelephone 200 An exemplary connection scheme of coupling elements 204a-204c of the present invention is seen in FIGURE 2A. In FIGURE 2A, the coupling elements 204a and 204b are connected together, and electrically insulated from the ground plane 102, while the connector 204c is directly connected to a ground plane 102. For the transmission of signals using In the present invention, portable radiotelephone RF signals 200 (see FIGURE IB) are transmitted over the air by the antenna 20. The coupling elements 204a and 204b decouple the RF energy from the antenna 204 and pass it to the matching circuit 110, which provides an impedance matching between the auxiliary power generator 302 and the antenna coupler 100. The auxiliary generator optional power 302, increases the energy of the RF signal coupled from the antenna 204 and passes the resulting high energy signal to the external antenna 304 for transmission over air. For reception, a reverse signal flow occurs. The FR signals received by the external antenna 304 are optionally passed through an auxiliary power generator 302, and the matching circuit 110 for coupling the elements 204a and 204b, wherein the signal energy is coupled to the antenna 204 of the portable radiotelephone 200. FIG. 2B illustrates an alternative connection scheme of the coupling elements 204a-204c. FIGURE 2B is similar to FIGURE 2A, except that it is the two external coupling elements, 204a and 204c, which are both connected to the ground plane 102, and only the internal coupling element 204b is electrically insulated to the ground connection plane 102 and connected to the circuit of adaptation 110. This alternative arrangement of FIGURE 2B has different FR characteristics than those of FIGURE 2A, and may be more suitable for different ranges of operating frequency or antenna structures. Referring now to FIGURE IB, the grounding bolts 206a and 206b make electrical contact with the mounting screws 202a and 202b (see FIGURE 1A) of the portable radiotelephone 200. Since these mounting screws penetrate the internal electromagnetic shield (not shown) enclosing the internal components of the portable radiotelephone 200, improve contact between the grounding of the antenna coupler 100 and the portable radiotelephone 200. Although there is typically no direct contact between the mounting screws 202a and 202b of the radiotelephone Portable 200 and the protective shield against internal electromagnetic interference (EMI) (not shown), the screws pass through the edges of the protective shield, providing sufficient potential for grounding. In the preferred embodiment, the grounding bolts 206a and 206b are spring loaded to ensure reliable contact with the mounting screws 202a and 202b. Alternatively, the radiotelephone 200 may be designed so that the mounting screws 202a and 202b make direct physical contact with the inner shield EMI. Direct contact can also be made between the ground plane 102 and the internal ground connection of the portable radiotelephone 200, through the grounding pin 206c, which contacts the grounding port of the battery 208 of the portable radiotelephone 200. In this optional configuration, the coupling between the internal ground connection of portable radiotelephone 200 and the ground plane 102 can also be effected. It should be understood that although the exemplary embodiment illustrated in FIGURE 1 comprises three connection pins to ground 206a, 206b and 206c, alternative embodiments may comprise more or fewer bolts to perform the same function. In a second embodiment of the antenna coupler of the present invention, shown in FIGS. 3A and 3B, the coupling elements 204a, 204b and 204c of FIGURE 1, are replaced with a direct contact coupling bolt 404. The bolt of direct contact coupling 404 is mounted to, but electrically insulated from, the ground plane 102. The direct contact coupling bolt 404 makes physical contact with an internal component in the RF chain of the radiotelephone 200. For example, if an antenna 204 is encapsulated in an insulating material, such as a plastic, the direct contact coupling bolt 404, makes physical contact with the internal electrically conductive portion 408 of the antenna 204, through a small opening 406 in the case external protector of antenna 204, as shown in FIGURE 3A. Alternatively, the portable radiotelephone 200 may have a small opening in its protective case so that the direct contact coupling bolt 404 makes physical contact with the nut of the antenna 414 or antenna clip 412, or any suitable component in the FR chain of the circuit board 410, all internal to the portable radiotelephone 200. The direct contact of the coupling bolt 404 with an internal component of the RF chain of the portable radiotelephone 200 as shown in any of FIGURES 3A or 3B, obvious the need for the multiple coupler configuration associated with the coupling on the air, as shown in FIGURES 1 and 2. Again, it should be noted that the antenna 204 may be of a non-helical design, such as a rod or ring or other antenna design, as is known in the art. In a third embodiment of the antenna coupler 100 shown in FIGS. 4A and 4B, the coupling elements 204a-204c can be replaced by a helical coupler 504. In this embodiment, when the portable radiotelephone 200 is interconnected with the antenna coupler 100 , the antenna 204 is inserted along a longitudinal axis into the helical coupler 504. The helical coupler 504 is preferably constructed of a conductive wire, such as copper, steel or the like. The FR coupling is achieved on the air, similar to that of the coupling elements 204a-204c. However, in contrast to the semicircular arrangement of the coupling elements 204a-204c, as shown in FIGURE 1, the helical coupler 504 completely surrounds the antenna 204. Also, the helical coupler 504 is electrically isolated from the connection plane to ground 102. The embodiments of FIGURES 4A and 4B have different FR characteristics than those of FIGURES 1A and IB or 3A and 3B, and may be more suitable for different operating frequency ranges or antenna structures. Frequently, a portable radiotelephone 200 is designed to operate in two separate frequency bands, such as operation in a frequency band designed for a personal communication system (PCS) and a second frequency band designed for telephony operation cell phone. When the portable radiotelephone 200 operates in two bands, it is desirable to provide suitable matching circuits for the antenna adapter 100 to maximize operation in each of the two bands. Some portable radiotelephones of the prior art include a terminal for direct coupling between the RF circuit of the radiotelephone and an external antenna. A switch (not shown) inside the radiotelephone, allows operation with the internal antenna or external antenna. However, internal switching results in an insertion loss and the subsequent decrease in FR output, even when the portable radiotelephone is used with the internal antenna. The dual-band antenna coupler of the present invention overcomes this drawback by eliminating the switching circuit of the internal antenna.

FIGURE 5A illustrates a dual band implementation of the antenna coupler 100. The external coupling member 204s is coupled to the ground plane 102, while the coupling elements 204a and 204b are electrically isolated from the ground plane 102. The internal coupling element 204b couples the RF energy of the antenna 204 (see FIGURE IB) to an adaptation circuit of a band 602. The adaptation circuit of a band 602 is designed to adapt the antenna 204 for the operation at frequencies in a first band. The coupling element 204a couples the RF energy of the antenna 204 to a two-band adaptation circuit 604. The two-band adaptation circuit 604 is designed to adapt the antenna 204 for operation at frequencies in a second band. The outputs of the one-band adaptation circuit 602 and the two-band adaptation circuit 604 are coupled to a selector switch 606. The selector switch 606 selects the output of one of the band adaptation circuits for coupling to the external antenna 304 The selector switch 606 may be any type of switching device, such as a block diplexer, diode switch, transmission line diplexer, transmission switch, passive circuit or the like. The operation of those conventional switching circuits is well known in the art and does not need to be described in more detail here. Also in FIGURE 5A an optional external control 608 is shown for selector switch 606. With this optional mode, selector switch 606 can be digitally controlled by signals from portable radiotelephone 200. As is known in the art, dual band radiotelephones typically they include a serial output port, which can be used to generate a control signal coupled to the optional external control 608. In this way, the selector switch 606 can be controlled by signals generated by the portable radiotelephone 200. An outline of alternative connection for coupling the elements 204a-204c is illustrated in FIGURE 5B. The operation of the circuit of FIGURE 5B is identical to that of FIGURE 5A, except that the external coupling member 204a is electrically connected to a ground plane 102 in FIGURE 5B, while the external coupling element 204s it is electrically isolated from the ground plane and is used to couple the RF energy of the antenna 204 to the two-band adaptation circuit 604. The alternative arrangement of FIGURE 5B has different FR characteristics than that of FIGURE 2A, and may be more suitable for different frequency ranges of operation or antenna structures.

The dual band adaptation circuit of the present invention is also useful with the antenna coupler embodiments 100 illustrated in FIGS. 3A, 3B. 4A and 4B. In the embodiments of the antenna coupler 100 illustrated in FIGS. 5A and 5B, separate inputs are provided to an adaptation circuit of a band 602 and the two-band adaptation circuit 604 from several antenna coupling elements 204a-204c. However, in the embodiments of the antenna coupler 100 illustrated in FIGS. 3A, 3B, 4A and 4B, the RF signals are coupled from the portable radiotelephone 200 via the direct contact coupling bolt 404 (see FIGURES 3A and 3B). ) or by the helical coupler 504 (see FIGURES 4A and 4B). In FIGURE 6, the one-band adaptation circuit 602 and the two-band adaptation circuit 604 are coupled to a single antenna cable 700 via the switching circuit 702. The switching circuit 704 couples the RF energy of the antenna 204 to the adaptation circuit for the appropriate frequency band. The one-band adaptation circuit 602, the two-band adaptation circuit 604, and the selector switch 606 operate in the manner described above. The switching circuit 702 can be one of a number of known switching circuits, such as a block diplexer, diode switch, transmission line diplexer, transmission switch, passive circuit or the like. FIGURE 6 also illustrates an optional external control line 704 for controlling the operation of the switching circuit 702. As discussed above with respect to the selector switch 606, the radiotelephone 200 can provide digital control signals through a serial port for controlling the selection of both the selector switch 606 and the switching circuit 702. As those skilled in the art will recognize, the electrical circuit for the one-band adaptation circuit 602 and the two-band adaptation circuit 604 can be combined into one dual band adaptation circuit 800, illustrated in FIGURE 7. The dual band adaptation circuit 800 is designed for optimized operation on both frequency bands. However, as those skilled in the art can appreciate, a combination of the matching circuit is not as optimal as two individual circuits, such as a band matching circuit 602 and the two band matching circuit 604. However, The advantage of a single dual band adaptation circuit 800 is that it eliminates the need for selector switch 606 and switching circuit 702, if the antenna coupler 100 uses a single antenna cable 700. However, there are techniques for optimizing the operation of the two-band adaptation circuit 800. For operation with the helical coupler 504 (see FIGURES 4A and 4B), the helical coupler 504 can be optimized for dual-band operation with the antenna 204. Alternatively, the Dual band 800 adaptation circuit can be optimized to operate on two frequency bands, through the use of concentrated passive components, or through s the use of the transmission line adaptation using tuner adapters 802 and 804 as resonators for the operation of a PCS and cellular band, respectively. In each of the above embodiments, the antenna coupler 100 can be encapsulated in a plastic or other non-conductive housing assembly 300 or the like, to protect the coupling elements 204a-204c, the grounding bolts 206a-206c and the grounding plane 102 against damage, and to provide support to the structure of the antenna coupler 100. Preferably, the housing assembly 300 encapsulates the antenna coupler 100 would have a receptacle on the top face to receive and capture from securely the portable radiotelephone 200, so that the antenna 204 is brought into close proximity with the coupling elements 204a-204c, and the grounding pins 206a-206c are physically aligned with, and securely coupled with, the externally accessible ground connections on the portable radiotelephone 200, that is, the mounting screws 202 and / or the battery ground connection port 206. Clearly, many different designs can be used for mounting the housing 300 without departing from the inventive concept of the present invention. For example, the housing assembly 300 can be fixedly mounted to a vehicle instrument panel. Alternatively, the housing assembly 300 may be a more manageable portable design, which may be held near the user's head. The above description of the preferred embodiments was provided to enable any person skilled in the art to make or use the present invention. The different modifications of these modalities will be readily apparent to those skilled in the art, and the generic principles defined therein can be applied to other modalities, without the use of the inventive faculty. Thus, the present invention is not intended to be limited to the modalities shown therein, but according to the broadest scope consistent with the principles and novel features described in it. It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Claims (20)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property.

1. An antenna coupling device for coupling radio frequency signals and a communication device having an antenna, and at least one externally accessible ground connection point, the communication device operates in two frequency bands, the coupling device antenna comprises: a ground connection plane having a top surface; an antenna coupler mounted on the upper surface of the ground plane, for coupling radio signals to, and of the antenna of the communication device; at least one grounding bolt, coupled to the upper surface of the grounding plane, for contacting at least one externally accessible ground connection point; and an adaptation circuit coupled to the antenna coupler to generate a predetermined impedance for adapting the antenna coupler to the antenna of the communication device, to each of the first and second frequency bands. The coupling device according to claim 1, characterized in that the ground connection plane includes first and second vertical portions in contact, mounted on the upper surface, the first and second vertical portions in contact, are placed in a relation substantially orthogonal to each other and to the upper surface. The coupling device according to claim 1, characterized in that the adaptation comprises a first adaptation circuit for the operation of the communication device in a first of the two frequency bands, and a second adaptation circuit for the operation of the communication device in a second of the two frequency bands. 4. The coupling device according to claim 3, characterized in that the first and second adaptation circuits each have an independent output terminal, the coupler further includes a selection circuit coupled to the first and second output terminals. of the adaptation circuit, to couple the selected one of the independent output terminals to an output terminal of the device. The coupling device according to claim 1, characterized in that the antenna coupler comprises a plurality of curved metal strips facing upwards, a first of the curved strips being electrically insulated from the ground plane for coupling signals of radio a, and of the antenna of the communication device, when the communication device is operating in a first of the two frequency bands, a second the curved bands, is electrically isolated from the ground plane to couple radio signals to , and of the antenna of the communication device, when the communication device is operating in a second of the two frequency bands, and a third of the metal curved bands is electrically coupled to the ground connection plane. The coupling device according to claim 5, characterized in that the adaptation circuit comprises a first portion of the adaptation circuit having an input terminal for adapting the antenna of the communication device, when the communication device is operating in the first frequency band and a second portion of the matching circuit having an input terminal to adapt the antenna of the communication device, when the communication device is operating in the second frequency band, the first input terminal of the portion of the adaptation circuit is coupled to the first of the curved bands, the second input terminal of the adaptation circuit portion is coupled to the second of the curved bands. 7. The coupling device according to claim 1, characterized in that the antenna coupler comprises a metal pin sized to allow physical contact with the antenna of the communication device, when the communication device operates with the coupling device. The coupling device according to claim 7, characterized in that the adaptation circuit is a dual-band adaptation circuit, coupled to the antenna coupler to generate a predetermined impedance to substantially adapt the antenna coupler to the antenna of the device of communication, to each of the first and second frequency bands. The coupling device according to claim 7, characterized in that the adaptation circuit comprises a first portion of the adaptation circuit, for the operation of the communication device in a first of the two frequency bands, and a second portion of the adaptation circuit for the operation of the communication device in a second of the two frequency bands, the coupling device further includes a switching circuit coupled between the metal bolt and the first and second portions of the adaptation circuit, for selecting one of the first and second matching circuits for operation with the antenna coupler, the switching circuit couples the metal pin to the first portion of the matching circuit for the operation of the communication device in the first frequency band and couples the metal bolt to the second portion of the adaptation circuit for the operation n of the communication device in the second frequency band. The antenna coupler according to claim 1, characterized in that the antenna coupler comprises a helical wire to surround at least a portion of the antenna of the communication device, when the communication device operates with the coupling device. 11. An antenna coupling device for coupling radio frequency signals of a communication device having an internal antenna, and at least one externally accessible ground connection point, the communication device operates in two frequency bands, the Antenna coupler is characterized in that it comprises: a connector connectable to an external antenna; a ground connection plane having a top surface and sized to adapt the communication device; an antenna coupler mounted on the upper surface of the ground plane, for the coupling of radio signals between the antenna of the communication device and the external antenna connector; at least one grounding pin, coupled to the upper surface of the grounding plane, to make contact with an externally accessible grounding point; and an adaptation circuit coupled to the antenna coupler for receiving the radio frequency signals, and generating a predetermined impedance for adapting the antenna coupler to the antenna of the communication device and to the external antenna connector to each of the first and second second frequency bands. The coupling device according to claim 11, characterized in that the grounding plane includes first and second vertical portions in contact, mounted on the upper surface, the first and second vertical portions in contact, are placed in a relation substantially orthogonal to each other and to the upper surface of the ground connection plane. The coupling device according to claim 11, characterized in that it also includes an external amplifier operatively coupled between the adaptation circuit and the external antenna connector, to amplify signals between the antenna of the communication device and the external antenna connector. The coupling device according to claim 11, characterized in that the coupler comprises a plurality of curved metal strips facing upwards, a first of the metal strips being electrically isolated from the ground plane for coupling radio signals between the antenna of the communication device and the external antenna, when the communication device is operating in a first of the two frequency bands, a second of the metal bands is electrically isolated from the ground plane to couple the signals of radio between the antenna of the communication device and the external antenna, when the communication device is operating in a second of the two frequency bands, and a third of the metal bands is electrically coupled to the ground plane. The coupling device according to claim 14, characterized in that the adaptation circuit comprises a first adaptation circuit having an input terminal for adapting the antenna of the communication device, when the communication device is operating in the first frequency band and a second matching circuit, having an input terminal for adapting the antenna of the communication device, when the communication device is operating in the second frequency band, the first input terminal of the matching circuit is coupled to the first metal band, the second input terminal of the matching circuit is coupled to the second metal band. The coupling device according to claim 11, characterized in that the antenna coupler comprises a metal bolt dimensioned to allow physical contact with the antenna of the communication device when the communication device operates with the coupling device. The coupling device according to claim 16, characterized in that the adaptation circuit is a dual-band adaptation circuit, coupled to the antenna coupler to generate a predetermined impedance to substantially adapt the antenna coupler to the antenna of the device of communication to each of the first and second frequency bands. 18. The coupling device according to claim 16, characterized in that the adaptation circuit comprises a first adaptation circuit for the operation of the communication device in a first of the two frequency bands and a second adaptation circuit for the operation of the communication device in a second of the two bands of communication. frequency, the coupling device further includes a switching circuit coupled between the metal bolt and the first and second matching circuits, to select one of the first and second matching circuits for operation with the antenna coupler, the switching circuit couples the metal bolt to the first adaptation, for the operation of the communication device in the first frequency band and couples the metal bolt to the second adaptation for the operation of the communication device in the second frequency band. The antenna coupler according to claim 11, characterized in that the antenna coupler comprises a helical wire to surround at least a portion of the antenna of the communication device, when the communication device operates with the coupling device. The coupling device according to claim 11, characterized in that the adaptation circuit has first and second output terminals for the operation of the communication device of the first and second bands, respectively, the coupler also includes a circuit selection coupled to the first and second output terminals, for coupling a selected one of the first and second output terminals to an output terminal of the device, with the first output terminal being selected for operation of the communication device in the first frequency band and the second output terminal being selected for the operation of the communication device in the second frequency band.