Abstract:
A flip or calm-shell style mobile terminal comprises a mechanical hinge that doubles as an inverted-F antenna for auxiliary communication purposes such as with a Bluetooth transceiver or a GPS receiver.

Description:
BACKGROUND OF THE INVENTION 
     The present invention is directed to an antenna for use in a mobile terminal and particularly to an auxiliary antenna for use in a mobile terminal. 
     Mobile terminals, such as cellular phones, pagers, personal digital assistants, and the like have exploded into the public&#39;s consciousness. One recent innovation pioneered by a consortium of mobile terminal manufacturers is a communication technology called Bluetooth that operates in the ISM band at 2.4 to 2.485 GHz in the electromagnetic spectrum. Mobile terminals are being adapted to incorporate this technology. Mobile terminals are also being adapted to operate with position detection systems, such as the Global Positioning System (GPS). GPS operates at 1.57542 GHz. 
     Due to the fact that these technologies operate at frequencies different from those normally associated with wireless communications, mobile terminals need additional, or at least different, antennas to function properly with these technologies. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention comprises using a mechanical hinge in a flip or clam-shell style mobile terminal as an inverted-F antenna for auxiliary communication purposes such as with a Bluetooth transceiver or a GPS receiver. In one embodiment, a first part of the hinge (a first hinge plate) is attached to the signal line of the RF printed circuit board of the mobile terminal by a fastener such as a screw. A second screw adjacent to the first screw is attached between the ground of the RF printed circuit board and the hinge. Together the first part and the two screws form an inverted-F antenna. A second part of the hinge (a second hinge plate) is coupled to the first part and forms the remainder of the mechanical hinge. In some embodiments, meanders are used to lengthen the electrical length of the first part so as to achieve an optimal operating frequency. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a communication environment that may include a wireless network for use with the present invention; 
         FIG. 2  illustrates a mobile terminal that may be adapted for use with the present invention; 
         FIG. 3  illustrates a perspective view of a flip-type mobile terminal suitable for use with the present invention; 
         FIG. 4  illustrates one embodiment of an antenna constructed according to the present invention; and 
         FIG. 5  illustrates a second embodiment of an antenna with meanders constructed according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is directed to an improved antenna arrangement in flip-type mobile terminals. In particular, the present invention provides an inverted F-antenna integrated into a hinge. A “hinge” as used herein includes both hinge plates and pivot area. It should be appreciated that while the hinges illustrated herein include a pin as the pivot, they may also be living hinges if needed or desired. This additional antenna allows the mobile terminal to communicate at another frequency while allowing isolation between the antennas of the mobile terminal to reduce crosstalk and other electromagnetic interference. 
     As illustrated in  FIG. 1 , a communication environment  10  may include a mobile network  40 , a location detection network  70 , and a Bluetooth network  80 . A mobile terminal  100  may be positioned in one or more of these networks. 
     Mobile network  40  may comprise, amongst other elements, an MSC  42  and a base station  50 . MSC  42  may be communicatively coupled to the Public Switched Telephone Network (PSTN)  20  or other mobile networks  40  within the Public Land Mobile Network (PLMN, not shown) as is conventional. The operation of mobile network  40 , and mobile terminal  100  within the mobile network  40 , are well documented in various standards such as TIA/EIA-136, Digital Advance Mobile Phone Service (D-AMPS), European Total Access Communication System (ETACS), Code Division Multiple Access (CDMA), Global System for Mobile Communication (GSM), Pacific Digital Cellular (PDC), and the like, the standards and documentation of which are herein incorporated by reference. 
     Location detection network  70  may be a satellite-based system, a terrestrial system or some hybrid thereof. Location detection network  70  is illustrated as a satellite system comprising one or more satellites  72 . The most common location detection system is the Global Positioning System (GPS), although the Russian equivalent, GLONASS, is another option. Other systems may likewise be available. Typically, satellites  72  communicate with mobile terminals  100  over a different frequency than that on which the mobile terminals  100  communicate with the mobile network  40 . For example, GPS satellites communicate at 1.57542 GHz. The GPS standards are partially publicly available at http://www.navcen.uscg.mil/pubs/gps/icd200/icd200c.pdf and are hereby incorporated by reference. 
     Bluetooth network  80  may comprise a Bluetooth enabled computer  82  or other Bluetooth enabled device such as another mobile terminal  100 , a vehicle or the like as needed or desired. Bluetooth is well documented at www.bluetooth.com. In particular, the specifications, volumes 1 and 2 are hereby incorporated by reference in their entirety. These are publicly available at http://www.bluetooth.com/developer/specification/specification.asp. Bluetooth communications likewise communicate with mobile terminals  100  over a different frequency than that on which the mobile terminals  100  communicate with the mobile network  40 . In particular, Bluetooth enabled devices communicate at approximately 2.4 GHz in the ISM band. 
     The present invention is adapted for use in the mobile terminal  100  to enable mobile terminal  100  to communicate with the various networks within communication environment  10 . However, a more complete understanding of the mobile terminal  100  may be helpful. Turning now to  FIG. 2 , a block diagram of a mobile terminal  100  is illustrated. Mobile terminal  100  typically includes a controller  122 , an operator interface  126 , a transmitter  138 , a receiver  150 , and a primary antenna assembly  158 . Operator interface  126  typically includes a display  128 , keypad  130 , interface control  132 , microphone  134 , and a speaker  136 . Display  128  allows the operator to see dialed digits, call status, and other service information. Keypad  130  allows the operator to dial numbers, enter commands, and select options. Interface control  132  interfaces the display  128  and keypad  130  with the controller  122 . Microphone  134  receives acoustic signals from the user and converts the acoustic signals to an analog electrical signal. Speaker  136  converts analog electrical signals from the receiver  150  to acoustic signals that can be heard by the user. 
     The analog electrical signal from the microphone  134  is supplied to the transmitter  138 . Transmitter  138  includes an analog to digital converter  140 , a digital signal processor  142 , and a phase modulator and RF amplifier  148 . Analog to digital converter  140  changes the analog electrical signal from the microphone  134  into a digital signal. The digital signal is passed to the digital signal processor (DSP)  142 , which contains a speech coder  144  and channel coder  146 . Speech coder  144  compresses the digital signal and the channel coder  146  inserts error detection, error correction and signaling information. DSP  142  may include, or may work in conjunction with, a DTMF tone generator (not shown). The compressed and encoded signal from the digital signal processor  142  is passed to the phase modulator and RF amplifier  148 , which are shown as a combined unit in FIG.  2 . The modulator converts the signal to a form that is suitable for transmission on an RF carrier. RF amplifier  148  then boosts the output of the modulator for transmission via the primary antenna assembly  158 . 
     Receiver  150  includes a receiver/amplifier  152 , digital signal processor  154 , and a digital to analog converter  156 . Signals received by the primary antenna assembly  158  are passed to the receiver/amplifier  152 , which shifts the frequency spectrum, and boosts the low-level RF signal to a level appropriate for input to the digital signal processor  154 . 
     Digital signal processor  154  typically includes an equalizer to compensate for phase and amplitude distortions in the channel corrupted signal, a demodulator for extracting bit sequences from the received signal, and a detector for determining transmitted bits based on the extracted sequences. A channel decoder detects and corrects channel errors in the received signal. The channel decoder also includes logic for separating control and signaling data from speech data. Control and signaling data are passed to the controller  122 . Speech data is processed by a speech decoder and passed to the digital to analog converter  156 . Digital signal processor  154 , may include, or may work in conjunction with, a DTMF tone detector (not shown). Digital to analog converter  156  converts the speech data into an analog signal that is applied to the speaker  136  to generate acoustic signals that can be heard by the user. 
     Together, the transmitter  138  and the receiver  150  are referred to herein as a voice communication transceiver. 
     Primary antenna assembly  158  is connected to the RF amplifier of the transmitter  138  and to the receiver/amplifier  152  of the receiver  150 . Primary antenna assembly  158  typically includes a duplexer  160  and an antenna  162 . Duplexer  160  permits full duplex communications over the antenna  162 . 
     Controller  122  coordinates the operation of the transmitter  138  and the receiver  150 , and may for instance take the form of a typical microprocessor. This microprocessor may be a dedicated or shared microprocessor and may be a single processor or multiple parallel processors as needed or desired. This coordination includes power control, channel selection, timing, as well as a host of other functions known in the art. Controller  122  inserts signaling messages into the transmitted signals and extracts signaling messages from the received signals. Controller  122  responds to any base station commands contained in the signaling messages, and implements those commands. When the user enters commands via the keypad  130 , the commands are transferred to the controller  122  for action. Memory  124  stores and supplies information at the direction of the controller  122  and preferably includes both volatile and non-volatile portions. It is expected that controller  122  and memory  124  as well as many of the other processing components described herein will be positioned on a printed circuit board  190  ( FIG. 4 ) as is conventional. 
     In addition to the above-described elements, the mobile terminal  100  may also include a location detector  164  in communication with the controller  122 . Location detector  164  may have its own antenna  300  discussed below. Location detector  164  may be a Global Positioning System (GPS) receiver or other satellite or terrestrial system as needed or desired. Typically, the location detector  164  will output a geocoordinate expressed as longitude, latitude, and, optionally, altitude coordinates corresponding to the present location of the mobile terminal  100 . 
     Mobile terminal  100  may also include a Bluetooth module  168  together with Bluetooth antenna  200 . Bluetooth is discussed above and reference is made thereto. Bluetooth module  168  is designed to comply with the standards set forth for Bluetooth and enable wireless communication at approximately 2.4 GHz between Bluetooth enabled devices. Controller  122  may control Bluetooth module  168  as needed or desired. 
     As noted, various antennas maybe associated with the mobile terminal  100 . Antennas operate most efficiently when they are one quarter the length of the signal desired to be received. Thus, to facilitate proper communication in a mobile terminal  100  amongst the various networks  40 ,  70 , and  80 , it may be desirable to have three different antennas. Further, many mobile terminals  100  are already designed to operate in two or three modes so as to communicate with different mobile networks  40  that may employ different standards alternatively requiring more antennas. Typically, a mobile terminal  100  may operate at one or more of the following frequency ranges: 824-894 MHz, 880-960 MHz, 1710-1880 MHz, and 1850-1990 MHz, depending on which standards with which it complies. 
     It is known to add antennas having the desired length to mobile terminals  100  to add additional functionality. However, these additional antennas require additional circuitry and additional space in or about the mobile terminals. Further, the antennas must be separated sufficiently to insure proper mutual isolation so as to reduce crosstalk or other forms of electromagnetic interference. While filters can be used to reduce crosstalk, filters for closely spaced antennas tend to be bulky and relatively expensive to achieve the performance required. Alternatively a “window” may be created which allows an internally positioned antenna to communicate through the body  170  ( FIG. 3 ) of the mobile terminal  100 . However, this imposes additional undesirable constraints on circuit board design. Thus, for antennas for Bluetooth or GPS applications, especial care must be taken to not interfere with the primary cellular antenna assembly  158 . 
     A mobile terminal  100  incorporating the present invention is illustrated in a perspective view in FIG.  3 . Mobile terminal  100  is a flip-type or clamshell-type mobile terminal having a body  170  and a flip portion  180  hingedly connected one to the other by hinges  172  and  174 . It should be appreciated that in some embodiments, only one hinge  172  may connect the flip portion  180  to the body  170 . Display  128  may be mounted on the mobile terminal  100 , and, in this case, on the flip portion  180 . However, it should be appreciated, that in some mobile terminals  100 , such as a cellular phone, the flip portion  180  may have no additional components. Mobile terminal  100  may also comprise a keypad  130 , a microphone  134  and a speaker mounted on body  170 . Again, it should be appreciated that some or all of these components instead could be mounted on the flip portion  180  if needed or desired. Primary antenna assembly  158  is shown as a stub antenna, but may include other classes of external or internal antennas designed to operate at conventional cellular frequencies or the like. 
     It should be appreciated that the term “mobile terminal” may include a cellular radiotelephone with or without a multi-line display, a Personal Communications System (PCS) terminal that may combine a cellular radiotelephone with data processing, facsimile and data communications capabilities; a PDA that can include a radiotelephone, pager, Internet/intranet access, Web browser, organizer, and/or calendar; and a conventional laptop and/or palmtop receiver or other appliance that includes a radiotelephone transceiver. Mobile terminals may also be referred to as “pervasive computing” devices. Thus, while the present discussion may be couched in terms of a phone and/or a laptop computer, the present invention is equally applicable to these other sorts of devices. The previous discussion was by way of example, and not intended to be limiting on the definition of a mobile terminal. 
     The present invention uses hinges  172  and/or  174  to act as the antennas for location detector  164  and/or the Bluetooth module  168 . While such applications may be of primary commercial importance at the present time, it should be appreciated that an antenna created within the hinges  172  or  174  may equally be adapted for other purposes or devices within the mobile terminal  100 , such as Asia&#39;s i-Mode, another frequency antenna to make the mobile terminal  100  dual-mode or even tri-mode, or the like as needed or desired. Further, in mobile terminals  100  that include two hinges  172 ,  174 , both hinges may be changed to antenna hinges according to the present invention. For example, a first hinge  172  could be adapted for Bluetooth performance and a second hinge  174  adapted for GPS reception. Other permutations on this concept will be readily apparent to those of ordinary skill in the art. 
       FIG. 4  illustrates a first embodiment of the present invention. In particular, a hinge, for the purposes of illustration, hinge  172 , connects the flip portion  180  to the body  170  of the mobile terminal  100 . Hinge  172  is formed from two parts, a first part  202  and a second part  204 . In the event the flip portion  180  includes a display  128 , hinge  172  is constructed to allow a flex-film line (constructed of a suitable polyimide material) to carry signals to the display from the body  170  and particularly from the controller  122  on the printed circuit board  190 . 
     First part  202  is spaced from and attached to the printed circuit board  190  by two fasteners  206  and  208  respectively. Together, the first part  202  and the fasteners  206 ,  208  form an inverted-F antenna. Suitable fasteners include screws or the like. Thus, the shank of the screw may space the first part  202  from the printed circuit board  190 . One fastener  206  acts as a connection to the ground plane of the printed circuit board  190 . The other fastener  208  acts as a the RF feed for the antenna  200 , connecting antenna  200  to the appropriate circuitry on the printed circuit board  190  such as the location detector  164  or the Bluetooth module  168 . Note that choosing which fastener acts as the ground connection and which acts as the RF signal connection is well understood. It should be appreciated that the ground feed and the RF feed could alternatively be provided by another structure that does not fasten the antenna  200  to the printed circuit board and that the antenna  200  may be held in place by fastening the antenna  200  to the body  170  of the mobile terminal  100 . It should be appreciated that the first part  202  and the fasteners  206  and  208  need to be capable of receiving electromagnetic signals, and thus are likely to be metal. Further, the spacing of the fasteners  206 ,  208  may be varied to achieve impedance matching or otherwise improve performance. 
     While dimensions of the hinge  172  are not critical to the present invention, sample appropriate dimensions are as follows: first part  202  length 25 mm, height 4 mm, and width 5 mm; second part  204  length 30 mm, height 0.02 mm, and width 7 mm. In general, the size of the two parts  202  and  204  will be dictated by the mechanical strength requirements of the hinge  172 . Angle Θ represents the angle between first part  202  and second part  204 . In one embodiment, antenna  200  should function as desired regardless of the angle Θ. This, however, may be somewhat dependent upon the operating frequency of the antenna  200 . 
     A second embodiment is illustrated in FIG.  5 . In this embodiment, especially adapted for GPS reception, antenna  300  comprises a first part  302  and a second part  304 . Similarly to the previous embodiment, one fastener (not shown) may connect part  302  to the signal line of the RF printed circuit board and another fastener (not shown) may connect the ground of the RF printed circuit board to part  302  is required. This has been achieved here using plates  320 ,  322  respectively as illustrated. Note that plate  320  may be thicker than plate  322 . First part  302  includes a meander  310  to make it electrically longer without changing the axial length of the first part  302 . Second part  306  may likewise be coated with a plastic film so as not to short out the meanders  310  when the hinge  172  is in a closed position. For a further discussion of meander antennas in the field of mobile terminals, reference is made to application Ser. No. 09/089,433, which is hereby incorporated by reference in its entirety. Alternatively, a film may be positioned atop meanders  310  to perform the same function. Other alternate techniques to isolate the parts  304  and  306  may also occur to those of ordinary skill in the art. 
     The present invention may, of course, be carried out in other specific ways than those herein set forth without departing from the scope and the essential characteristics of the invention. The present embodiments are therefore to be construed in all aspects as illustrative and not restrictive and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.