MXPA97009334A

MXPA97009334A - Antenna coupler for a portable radiotelephone

Info

Publication number: MXPA97009334A
Application number: MXPA/A/1997/009334A
Authority: MX
Inventors: Maldonado David
Original assignee: Qualcomm Incorporated
Priority date: 1996-04-02
Filing date: 1997-12-01
Publication date: 1998-02-01

Abstract

A novel and improved antenna coupler (100) useful in an adapter for a portable radiotelephone (200). In a first embodiment, a plurality of curved bands (204a-204c) of metal are positioned on a ground plane (102), with at least one of the plurality of curved bands of metal (204a-204c) being electrically isolated from the ground plane (102) so as to couple RF signals to and from the antenna (204) of a portable telephone (200). At least one ground pin (206a, 206b, 206c) is also mounted on the ground plane (102). When a portable radiotelephone (200) is interfaced with the antenna coupler (100), the at least one ground pin (206a, 206b, 206c) makes electrical contact with assembly screws (202a, 202b) or an external ground pad (208) of a battery charging port on the portable radiotelephone (200). In a second embodiment, a coupling pin (404) makes direct contact with a component of the RF chain of the portable radiotelephone (200). In a third embodiment, a helical coupler (504) surrounds the antenna (204) of the portable radiotelephone (200).

Description

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 a new and improved 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 through radio frequencies (RF). Typically, these portable radiotelephones operate at relatively low power levels in order to conserve battery power and increase talk time. However, when alternative available energy means exist, such as a vehicle battery when driving, or a conventional electrical outlet when indoors, the user of the portable radiotelephone frequently employs special adapters to take advantage of the higher available power supply. . For example, there are many vehicle adapters that transform the power supply generated by the vehicle to a suitable level for use by the portable telephone, and also couple the RF signals to and from the portable radio telephone for use with an external power amplifier and antenna. . Additionally, these adapters may include a "hands-free" kit that includes an auxiliary microphone and horn. In this way, the user can take advantage of higher energy transmission and hands-free conversation without sacrificing battery time, and still be able to carry the same portable radiotelephone with him when he leaves his car. In order to couple the RF signal to and from the portable radiotelephone, a typical vehicular adapter uses an inductive coupler placed near the portable radiotelephone's antenna. However, this technique can result in a significant amount of RF signal energy loss, particularly when an insufficient RF return path is provided, or to ground for the portable radiotelephone while it is in the adapter. Since the internal components of a typical portable radiotelephone are enclosed in an electromagnetic interference shield (EMI) to prevent electromagnetic dispersion energy from leaking out of the radiotelephone receptacle, prior art vehicle adapters have not been able to achieve sufficient RF return path to the portable radiotelephone.

SUMMARY OF THE INVENTION The present invention is a novel and improved antenna coupler useful in an adapter for a portable radiotelephone. In a first embodiment, a plurality of curved metal bands are placed on a flat base, with at least one of the plurality of curved metal bands electrically separated from the base plane in order to couple RF signals to and from the antenna of a Portable Phone. At least one base connector is also mounted on the base with artificial polarization. When a portable radiotelephone communicates with the antenna coupler, the at least one base connector makes electrical contact with the assembly screws in the portable radiotelephone. Since the assembly screws penetrate the EMI shield, a complete return ground path of RF is provided to the portable radiotelephone. Optionally a base connector makes direct electrical contact with an external base assembler of a portable charging port of the portable radiotelephone, providing an alternate means of coupling the base of the radiotelephone to the base plane of the antenna coupler. In a second embodiment, a coupling connector makes direct contact with a component of the RF chain of the portable radiotelephone, such as the antenna of the portable radiotelephone. In the second embodiment, there is no need to couple the signal over the air by the curved metal bands. In a third modality, a helical coupler surrounds the portable radiotelephone antenna, coupling the RF signals over the air. The RF signals coupled from the antenna of the portable radiotelephone by the antenna coupler of the present invention are passed through an impedance comparison circuit, and optionally to an energy amplifier, where they are subsequently transmitted over an auxiliary antenna external Conversely, the signals received by the external auxiliary antenna are coupled to the portable radiotelephone by the antenna coupler of the present invention. 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 are identified correspondingly through of all and in which: Figure IA is an illustration of an exemplary portable radiotelephone suitable for use with the present invention; Figure IB is an illustration of a first embodiment of the antenna coupler of the present invention, which communicates 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 alternate 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 communicating with a direct connection to an exemplary portable radiotelephone antenna, shown in a partially exploded view; Figure 3B is an illustration of a second embodiment of the coupling elements of the present invention communicating 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 communicating with an exemplary portable radiotelephone; and Figure 4B is an illustration of the helical coupler of the third embodiment of the present invention communicating with an antenna of an exemplary portable radiotelephone. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. IB, a first embodiment of the antenna coupler 100 of the present invention comprises a base plane 102, coupling elements 204a, 204b, and 204c, base connectors 206a, and 206b, and a Optional base connector 206c. Coupling elements 204a, 204b and 204c are preferably constructed of curved bands, facing vertically, of a conductive material, such as copper, steel or the like. When the portable radiotelephone 200 communicates with the antenna coupler 100, the coupling elements 204a, 204b and 204c receive the retracted helix antenna 204 of the portable radiotelephone 200 and couple the RF signals to and from the antenna 204. The elements of coupling 204a, 204b and 204c are constructed and positioned in such a way that when the portable radiotelephone 200 communicates with the antenna coupler 100, the coupling elements 204a, 204b and 204c extend in a semicircular installation, each covering a quarter of a second. the antenna circumference 204. It should be noted that the antenna 204 may also be of non-helical construction as is known in the art, such as a rod or loop antenna. It should also be noted that the portable radiotelephone 200 can generally be any type of mobile communication device, such as a cellular or PCS radiotelephone, or a wireless local network communication device. The coupling elements 204a, 204b and 204c are mounted on a respective coupling base to the base plane 102. In the preferred embodiment, the base plane 102 is a wiring panel printed on both sides (PWB). However, a single-sided PWB will also provide a construction suitable for the base plane 102 or any large base covered with a layer of conductive material. In order to couple RF energy from the antenna 204, at least one of the coupling elements 204a, 204b and 204c is electrically separated from the base plane 102. The base plane 102 also serves to electrically couple the base connectors 206a, 206b, and (optionally) 206c to at least one of the coupling elements 204a, 204b and 204c. That is, each of the base connectors 206a-206c, the base plane 102 and at least one of the coupling elements 204a-204c share the same electrical base potential. As such, a complete RF signal path can be provided to couple the RF signals to and from the antenna 204 by connecting base connectors 206a, 206b, and (optionally) 206c to a suitable base on the portable radiotelephone 200. A Exemplary connection scheme of the 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 separated from the base plane 102, while the connector 204c is directly connected to the base plane 102. For the signal transmission using the present invention, the RF signals from of the portable radiotelephone 200 (see figure IB) are transmitted over the air by the antenna 204. The coupling elements 204a and 204b decouple the RF energy from the antenna 204 and pass it to the comparison circuit 110, which provides a comparison of impedance between the power amplifier 302 and the antenna coupler 100. The optional power amplifier 302 increases the power of the RF signal coupled from the antenna 204 and passes the resulting high power signal to the external antenna 304 for a transmission in the air. For its reception, the reverse signal flow appears. The RF signals received by the external antenna 304 are optionally passed through the power amplifier 302 and the comparison circuit 110 to the coupling elements 204a and 204b where the signal energy is coupled to the antenna 204 of the portable radiotelephone 200. An alternative connection scheme of coupling elements 204a-204c is illustrated in Figure 2B. Figure 2B is similar to Figure 2A, except that this is the two external coupling elements, 204a and 204c which are both connected to the base plane 102, and only the internal coupling elements 204b are electrically separated from the base plane 102 and it is connected to the comparison circuit 110. This alternative installation of Figure 2B has RF characteristics different from those of Figure 2A, and may be more suitable for different operating frequency antenna ranges or structures. Referring now to FIG. IB, the base connectors 206a and 206b make electrical contact with the assembly screws 202a and 202b (see FIG. IA) of the portable radiotelephone 200. Since these assembly screws penetrate the internal electromagnetic shield (not shown) enclosing the internal components of the portable radiotelephone 200, improve the contact between the base of the antenna coupler 100 and the portable radiotelephone 200. Although typically there is no direct contact between the assembly screws 202a and 202b of the portable radiotelephone 200 and The internal electromagnetic interference shield (EMI) (not shown), the screws pass through the edges of the shield, providing sufficient base potential. In the preferred embodiment, the base connectors 206a and 206b are spring loaded to ensure reliable contact with the assembly screws 202a and 202b. Alternatively, the radiotelephone 200 can be designed in such a way that the assembly screws 202a and 202b make direct physical contact with the internal EMI shield. Direct contact can also be made between the base plane 102 and the internal base of the portable radiotelephone 200 through the base connector 206c, which makes contact with the battery base port 208 of the portable radiotelephone 200. In this optional configuration, it can also be The coupling between the internal base of the portable radiotelephone 200 and the base plane 102 should be carried out. It should be understood that although the exemplary embodiment illustrated in FIG. 1 comprises three base connectors 206a, 206b and 206c, the alternate embodiments may comprise more or less connectors to carry out this 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 FIG. 1 are replaced with a direct contact coupling connector 404. The coupling connector by direct contact 404 is mounted on, but electrically separated from, the base plane 102. The direct contact coupling connector 404 makes physical contact - Í ¬ There is an internal component in the RF chain of the radiotelephone 200. For example, if the antenna 204 is enclosed in an insulating material, such as plastic, the direct contact coupling connector 404 makes physical contact with the internal electrically conductive portion 408 of the antenna. the antenna 204 through a small opening 406 in the outer shield housing of the antenna 204, as shown in Figure 3A. Alternatively, the portable radiotelephone 200 may have a small opening in its protective receptacle so that the direct contact coupling connector 404 makes physical contact with the antenna nut 414 or the antenna holder 412, or any suitable component in the chain RF of the circuit panel 410, all internal to the portable radiotelephone 200. The direct contact of the coupling connector 404 to an internal component in the RF chain of the radiotelephone 200 as shown in either FIG. 3A or 3B avoids the need of the multiple coupler configuration associated with the coupling to the air as shown in Figures 1 and 2. Again, it should be noted that the antenna 204 may be of non-helical design such as a rod or loop or other antenna design as it is known in the matter. 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 communicates 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 RF coupling is carried out on the air, similar to that of the coupling elements 204a-204c. However, in contrast to the semicircular installation 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 separated from the base plane 102. The embodiment of Figures 4A and 4B has different RF characteristics to those of Figures 1 or 3A and 3B, and may be more suitable for frequency ranges or antenna structures of different operation. In each of the above embodiments, the antenna coupler 100 can be enclosed in a plastic or any other non-conductive housing assembly 300 or the like in order to protect the coupling members 204a-204c, the base connectors 206a from damage. -206c and the base plane 102 and to provide support to the structure of the antenna coupler 100.

Preferably, the housing assembly 300 enclosing the antenna coupler 100 would have a receptacle on the top face for securely receiving and capturing the portable radiotelephone 200 in such a manner that the antenna 204 is conducted within the closest proximity to the elements of the antenna. coupling 204a-204c, and the base connectors 206a-206c physically align with, and securely engage with, the externally accessible bases on the portable radiotelephone 200, i.e., the assembly screws 202 and / or the port. . battery base 206. Clearly, many different designs can be used for housing assembly 300 without departing from the inventive concept of the present invention. For example, the housing assembly 300 can be fixedly mounted to a vehicular instrument panel. Alternatively, the housing assembly 300 can be a design for holding with the most portable hand that can be held close to the user's head. The prior description of the preferred embodiments is provided to allow any person skilled in the art to make or use the present invention. The various modifications to these modalities will be readily apparent to those skilled in the art and the generic principles defined herein may be applied to other modalities without the use of the inventive faculty. In this way, the present invention is not intended to be limited to the modalities shown herein but to be in accordance with the broadest scope consistent with the principles and novel features set forth herein.

Claims

NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and therefore the property described in the following claims is claimed as property. 1. An antenna coupler for coupling radiofrequency signals from a communication device having an antenna and at least one externally accessible base point, said antenna coupler comprising: a base plane; means, mounted on an upper face of said base plane, for coupling radio signals to and from said antenna; and at least one base connector, coupled to said upper face of said base plane, for contacting said externally accessible base point. The antenna coupler according to claim 1, characterized in that said coupling means comprise a plurality of curved bands of metal facing upwards, electrically separating at least one of said curved metal bands from said base plane. The antenna coupler according to claim 1, characterized in that said coupling means comprise a metal connector for physically contacting said antenna. The antenna coupler according to claim 1, characterized in that said coupling means comprise a helical wire to surround said antenna. The antenna coupler according to claim 2, characterized in that said externally accessible base point is an assembly screw that penetrates an internal electromagnetic shield of said portable radiotelephone. 6. The antenna coupler according to claim 2, characterized in that said externally accessible base point is a base assembler of a battery charging port. The antenna coupler according to claim 3, characterized in that said externally accessible base point is an assembly screw that penetrates an internal electromagnetic shield of said portable radiotelephone. The antenna coupler according to claim 3, characterized in that said externally accessible base point is a base assembler of a battery charging port. The antenna coupler according to claim 4, characterized in that said externally accessible base point is an assembly screw that penetrates an internal electromagnetic shield of said portable radiotelephone. 10. The antenna coupler according to claim 4, characterized in that said externally accessible base point is a base assembler of a battery charging port. 11. An antenna coupler for coupling radiofrequency signals from a communication device having an antenna and at least one externally accessible base point, said antenna having an internal electrically conductive portion enclosed in an insulating material, said antenna coupler comprises: a base plane; a metal connector, mounted on an upper face of said base plane, for coupling radio signals to and from said antenna; and at least one base connector, coupled to said upper face of said base plane, for contacting said externally accessible base point. The antenna coupler according to claim 11, characterized in that said externally accessible base point is an assembly screw that penetrates an internal electromagnetic shield of said portable radiotelephone. The antenna coupler according to claim 11, characterized in that said externally accessible base point is a base assembler of a battery charging port. 14. A communication device adapter - l for coupling radiofrequency signals from a communication device having an antenna and at least one externally accessible base point, said communication device adapter comprises: a base element having a base plane; means, mounted on an upper face of said base plane, for coupling radio signals to and from said antenna; at least one base connector, coupled to said upper face of said base plane, for contacting said externally accessible base point; and a housing assembly, which includes said base element, said housing assembly having a receptacle on an upper face for receiving said communication device in such a manner that said antenna is placed in proximity to said means for coupling radio signals and said at unless a base connector contacts said externally accessible base point. The antenna coupler according to claim 14, characterized in that said coupling means comprises a plurality of curved bands of metal facing upwards, electrically separating at least one of said curved metal bands from said base plane. The antenna coupler according to claim 14, characterized in that said coupling means comprise a metal connector for physically contacting said antenna. The antenna coupler according to claim 14, characterized in that said coupling means comprise a helical wire to surround said antenna. 18. The antenna coupler according to claim 15, characterized in that said externally accessible base point is an assembly screw that penetrates an internal electromagnetic shield of said portable radiotelephone. 19. The antenna coupler according to claim 15, characterized in that said externally accessible base point is a base assembler of a battery charging port. The antenna coupler according to claim 16, characterized in that said externally accessible base point is an assembly screw that penetrates an internal electromagnetic shield of said portable radiotelephone. 21. The antenna coupler according to claim 16, characterized in that said externally accessible base point is a base assembler of said battery charging port. The antenna coupler according to claim 17, characterized in that said externally accessible base point is an assembly screw that penetrates an internal electromagnetic shield of said portable radiotelephone. 23. The antenna coupler according to claim 17, characterized in that said externally accessible base point is a base assembler of a battery charging port.