Patent Document

FIELD OF THE INVENTION 
     The present invention relates to antennas generally and, more particularly, to a method and/or architecture for an integrated GPS receiver and cellular transceiver module for automotive system bus applications. 
     BACKGROUND OF THE INVENTION 
     An antenna appropriate for receiving radio frequency (RF) signals transmitted by global positioning system (GPS) satellites is known. The positioning capabilities of the GPS have been incorporated into an automobile. For example, an antenna, such as M/A-COM part ANPC 128, can be used to receive a 1.575 Ghz radio frequency signal and send the received signal to a GPS module. The GPS module can receive the RF signal and generate positioning information and other NMEA (National Marine Electronics Association) data to a data bus of the vehicle. 
     Mobile communication devices, such as cellular telephones, allow calls to be made and received while operating a vehicle. Cellular telephones can also be used by vehicle operators to call for assistance. However, the many surfaces and mobile nature of automobiles make a challenging environment (i.e., multiple signal paths, reflections, weak signals, etc.) for receiving cellular signals. Also, hands on use of cellular telephones while driving is now recognized as posing a driving hazard. In many areas, the use of cellular telephones that are not hands free in automobiles is banned. 
     It would be desirable to have an integrated GPS receiver and cellular transceiver module especially packaged to connect directly to standard vehicle wiring harnesses and data buses. 
     SUMMARY OF THE INVENTION 
     The present invention concerns an integrated global positioning system (GPS) receiver and cellular transceiver module including (i) a printed circuit board substrate, (ii) a cellular multiband antenna disposed on the printed circuit board substrate, (ii) at least one first integrated circuit disposed on the printed circuit board substrate for processing signals from and signals to the cellular multiband antenna, (iii) a GPS antenna attached to the printed circuit board substrate, (iv) at least one second integrated circuit disposed on the printed circuit board substrate for processing signals from the GPS antenna and the at least one first integrated circuit, and (v) an electrical connector disposed on the printed circuit board substrate for establishing a data communication path between the at least one first and the at least one second integrated circuits and an electronic system of a vehicle, where the GPS receiver and cellular transceiver module is capable of being integrated into the electronic system of the vehicle. 
     The objects, features and advantages of the present invention include providing a method and/or architecture for an integrated GPS receiver and cellular transceiver module for automotive system bus applications that may (i) provide cellular voice processing through vehicle system bus, (ii) provide cellular GPRS packet data processing through vehicle system bus, (iii) transmit cellular voice data, (iv) transmit cellular GPRS packet data, (v) increase cold start and first time GPS position fix to nearly instantaneous with the use of Assisted GPS (A-GPS), (vi) allow GPS position/location data and cellular data to be transmitted anywhere in the world where there is mobile phone coverage, (vii) increase GPS performance in weak GPS signal environments with use of A-GPS, (viii) provide data for vehicle tracking systems, (ix) provide data for vehicle fleet tracking systems, (x) provide data for vehicle navigation systems, (xi) support theft deterrent systems, (xi) support theft recovery systems, (xii) provide information for advanced driver assistance systems (ADAS), and/or (xiii) provide GPS position data (e.g., latitude, longitude) to the vehicle system bus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other objects, features and advantages of the present invention will be apparent from the following detailed description and the appended claims and drawings in which: 
         FIG. 1  is a block diagram illustrating an example architecture in accordance with an embodiment of the present invention; 
         FIG. 2  is a block diagram illustrating an example GSM quad band data and voice module of  FIG. 1 ; 
         FIG. 3  is a diagram illustrating an example implementation of an integrated GPS receiver and cellular transceiver module in accordance with an example embodiment of the present invention; 
         FIG. 4  is a diagram illustrating the example implementation of an integrated GPS receiver and cellular transceiver module of  FIG. 2  with an alternate GPS antenna placement; 
         FIG. 5  is a diagram illustrating an example geometry and dimensions for a cellular quadband polarization diversity antenna in accordance with embodiments of the present invention; 
         FIG. 6  is a diagram illustrating various layers of a multi-layer printed circuit board substrate in accordance with embodiments of the present invention; and 
         FIG. 7  is a diagram illustrating an example application in accordance with a preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , a block diagram of a system  100  is shown illustrating an example architecture in accordance with a preferred embodiment of the present invention. The system  100  may implement an integrated GPS receiver and cellular transceiver module in accordance with a preferred embodiment of the present invention. The system  100  may comprise a block (or circuit)  102 , a block (or circuit)  104 , a block (or circuit)  106 , a block (or circuit)  108 , a block (or circuit)  110 , a block (or circuit)  112 , a block (or circuit)  114 , a block (or circuit)  116 , a block (or circuit)  118 , a block (or circuit)  120 , a block (or circuit)  122 , a block (or circuit)  124 , a block (or circuit)  126 , a block (or circuit)  128 , a block (or circuit)  130 , a block (or circuit)  132 , a block (or circuit)  134 , a block (or circuit)  136 , a block (or circuit)  138 , and a block (or circuit)  140 . 
     The block  102  may be implemented, in one example, as a GPS chip set. The block  104  may be implemented, in one example, as a GSM cellular module. In one example, the block  104  may comprise an independently certified drop-in module. For example, the block  104  may be implemented with LEON-G100/G200 Quad Band GSM/GPRS Data and Voice modules (e.g., available from U-blox America, 1902 Campus Commons Drive, Suite 310, Reston, Va. 20191). The block  106  may be implemented, in one example, as an MCU controller. The block  108  may be implemented, in one example, as a controller area network (CAN) transceiver. The block  110  may be implemented as a GPS antenna. In one example, the antenna  110  may be implemented as a microstrip patch antenna. The block  112  may be implemented as a surface acoustic wave (SAW) filter. The block  114  may be implemented as a low noise amplifier (LNA). The block  116  may be implemented as a crystal reference frequency oscillator (TCXO) for the GPS chip set  102 . The block  118  may be implemented as a real time clock (RTC) oscillator. The block  120  may be implemented as a low drop out (LDO) regulator for the real time clock oscillator  118 . The block  122  may be implemented as a data storage area. In one example, the storage area  122  may store operating software and/or data for the GPS chip set  102 . In one example, the block  122  may be implemented as a FLASH memory. The block  124  may be implemented as a low drop out (LDO) regulator for providing regulated voltage to a RF front end of the GPS chip set  102 . The block  126  may be implemented as a low drop out (LDO) regulator for providing a regulated voltage to a baseband portion of the GPS chip set  102 . The block  128  may be implemented, in one example, as a cellular quadband antenna. In one example, the block  128  may be implemented as an integrated folded inverted F quadband antenna. The block  130  may be implemented as a subscriber identity module (SIM). The block  132  may be implemented as a non-volatile memory. In one example, the block  132  may comprise an electrically erasable programmable read only memory (EEPROM). The block  134  may be implemented, in one example, as a CAN bus connection. The block  136  may be implemented as a main power supply for the system  100 . The block  138  may be implemented as a battery backup system. The block  140  may be implemented as a matching network. The block  140  may be optional. For example, depending on the efficiency of the implementation of quadband antenna  128 , the block  140  may be omitted without affecting performance of the system  100 . 
     The GPS chipset  102  may be implemented, in one example, with discrete surface mount devices (SMDs). In one example, the GPS chipset  102  may be implemented similarly to the GPS circuitry described in U.S. Pat. No. 6,272,349, which is herein incorporated by reference in its entirety. In one example, the GPS antenna  110  may be configured for receive-only operation of low level GPS satellite signals. The filter  112  may be implemented, in one example, as a passband filter operating at L1 GPS (e.g., 1575.42±1 MHz). The filter  112  may be configured to attenuate unwanted out-of-band RF signals to the GPS chip set  102  and periphery circuitry. The low noise amplifier  114  may be used to amplify low level GPS signals received by the system  100  with a low signal-to-noise ratio (SNR). The block  116  generally provides a crystal controlled reference frequency signal to the GPS chipset  102 . The GPS chip set  102  generally receives and processes the GPS signals. The block  132  may provide data storage for last known satellite fixes, module ID storage, etc. 
     In one example, the blocks  112  and  114  may be optional. For example, depending on the application, one or both of the blocks  112  and  114  may be omitted. In one example, the block  102  may be implemented with an internal amplifier and filter. For example, a GPS chipset may have an internal amplifier, filter, and automatic gain control already incorporated (e.g., in connection with anti-jamming capabilities). However, the inclusion of anti-jamming capabilities may affect dead reckoning (DR) performance of the GPS chipset. Dead reckoning generally refers to a process of estimating a current position based upon a previously determined position, or fix, and advancing that position based upon known or estimated speeds (e.g., from sensors within a vehicle) over an elapsed time, and course. 
     The cellular quadband antenna  128  may be configured for reception and transmission of mobile telephony signals. In one example, the antenna  128  may be configured for operation with a GSM (Global System for Mobile Communications: originally Groupe Spécial Mobile) mobile telephony system. The antenna  128  and the module  104  may support, in one example, GSM cellular telephone and General Packet Radio Service (GPRS) communication protocols. The antenna  128  may operate with signals in various GSM carrier ranges (e.g., 400/450 MHz, 850/900 MHz, 1800/1900 MHz, etc.). For example, second generation (2G) GSM networks may operate in the 900 or 1800 MHz bands. In locations where the 900 or 1800 MHz bands are already allocated (e.g., in the U.S. and Canada), 850 and 1900 MHz bands may be used. 
     The antenna  128  may be coupled to the module  104  either directly or via the matching network  140 . The matching network  140  generally matches an input/output impedance of the module  104  with an output/input impedance of the antenna  128  to maximize performance and/or minimize power consumption. The antenna  128  may be dimensioned (sized, scaled, etc.) such that the input/output impedance matches the specification of the module  104 . When the input/output impedance matches the specification of the module  104 , the matching network  140  may be omitted. 
     GSM modem chips need to be licensed in every country in which the part is sold. The module  104  is generally implemented as a pre-certified (e.g., licensed) drop-in chip to keep costs down. The module  104  may be connected to the GPS chipset  102 , the controller  106  and the SIM  130 . In addition to cellular telephony data, the module  104  may be configured to communicate assisted GPS (aGPS) related data to the GPS chipset  102  and transmit GPS position information via the quadband antenna  128 . The SIM  130  may be implemented, in one example, as a detachable smart card. The SIM  130  may contain subscriber information and phonebook data for a user. The SIM  130  generally allows the user to change vehicles including embodiments of the present invention while retaining their information. Alternatively, the user may change carriers (e.g., cellular phone service providers), while retaining the vehicle, simply by changing the SIM  130 . 
     The controller  106  generally connects with the GPS chipset  102 , the module  104  and the CAN transceiver  108 . The CAN transceiver  108  may be implemented with discrete surface mounted devices. The CAN transceiver  108  generally provides a transceiver interface to the CAN bus of the vehicle via the CAN connector  134 . However, other system busses and transceiver interfaces may be implemented to meet the design criteria of a particular implementation. The system  100  may also include a main power supply  136  that may receive a +12V power supply from the vehicle (e.g., alternator, battery, etc.). A back-up battery  138  may be implemented also to make the system  100  more robust. 
     Referring to  FIG. 2 , a block diagram is shown illustrating an example implementation of the GSM module  104  in  FIG. 1 . In one example, the module  104  may have a number of inputs that may receive a number of signals (e.g., ANTENNA DETECT, CHARGER, VCC(BATTERY), V_BCKP, POWER_ON, ADC, and EXTERNAL RESET), a connection for coupling the module  140  to the antenna  128 , and a number of input/outputs (e.g., GPIO, DDC (for GPS), UART, ANALOG AUDIO, DIGITAL AUDIO, and SIM CARD). 
     In one example, the GSM module  104  may comprise a block (or circuit)  150 , a block (or circuit)  152 , a block (or circuit)  154 , a block (or circuit)  156 , and a block (or circuit)  158 . The block  150  may be implemented as a single chip GPS/GPRS modem. The block  152  may be implemented as a power amplifier. The block  154  may be implemented as a standing acoustical wave (SAW) filter. The block  156  may be implemented as an antenna switch. The block  158  may be implemented as a memory. The block  150  generally receives/presents the input/outputs GPIO, DDC, UART, ANALOG AUDIO, DIGITAL AUDIO, and SIM CARD. The block  150  may connect to a first crystal and a second crystal. In one example, the block  150  may be connected to 26 MHz and 32.768 KHz crystals. 
     The block  150  may have an output that may present a signal to an input of the block  152  and an input that may receive a signal from the block  154 . An output of the block  152  may present a signal to the antenna  128 . An input of the block  154  may receive a signal from the antenna  128 . The block  150  may have an input/output that may connect with an input/output of the block  158 . 
     Referring to  FIG. 3 , a diagram is shown illustrating a printed circuit board (PCB) substrate  200  implemented in accordance with a preferred embodiment of the present invention. The PCB substrate  200  may have a first (front) side  202  and a second (back) side  204 . The front side  202  may have an area  206  in which the GPS receiver chip set  102  and associated circuitry may be mounted and an area  208  in which the cellular quadband transceiver  104  and associated circuitry may be mounted. The CAN transceiver  108  and associated circuitry may be mounted also in the area  208 . In one example, the GPS antenna  110  may be mounted parallel to the back surface  204  of the PCB substrate  200 . A ground plane  210  may be disposed between the GPS antenna  110  and the back surface  204  of the PCB substrate  200 . A via in the PCB substrate  200  may accept a contact pin of the antenna  110  to couple the antenna  110  with the GPS chipset  102 . 
     In one example, the front surface  202  of the PCB substrate  200  may have a metallization layer implementing the integrated cellular quadband antenna  128 . The metallization layer implementing the integrated cellular quadband antenna  128  may, in one example, be on a side of the PCB substrate  200  opposite from the side where the GPS antenna  110  is mounted. However, the integrated cellular quadband antenna  128  is generally implemented on an internal metallization layer to provide better shielding from the GPS signals. In one example, the integrated cellular quadband antenna  128  may be configured as a cellular quadband folded inverted F antenna. 
     The GPS antenna  110  generally has a right hand circular polarization (CP), whereas the cellular quadband antenna  128  generally provides polarization diversity while covering the bands of the cellular spectrum. Polarization diversity generally refers an ability to receive signals with more than one orientation. Polarization diversity may be obtained, in one example, by combining pairs of antennas with orthogonal polarizations (e.g., horizontal/vertical, ±slant 45°, Left-hand/Right-hand CP, etc.). Reflected signals may undergo polarization changes depending on the media. By pairing two complementary polarizations, polarization diversity may immunize a system from polarization mismatches that would otherwise cause signal fade. Additionally, such diversity is less susceptible to the near random orientations of transmitting antennas. Polarization diversity is useful in systems where a receiver is moving relative to the transmitter. 
     The metallization layer of the PCB  200  may have a portion  212  forming the integrated cellular quadband antenna  128  and a portion  214  providing a ground plane for the integrated cellular quadband antenna  128 . A feed (e.g., a microstrip transmission line) from the cellular module  104  to the cellular quadband antenna  128  may be buried within the layers of the PCB  200  for shielding and/or isolating the cellular portion from the GPS portion. The integrated cellular quadband antenna  128  may have a short-circuit stub connecting the antenna portion  212  to the ground plane portion  214 . 
     An arrow  216  generally indicates an orientation of the PCB substrate  200  with respect to a zenith of an automotive environment in which the PCB substrate  200  may be mounted. When a module incorporating the PCB substrate  200  is mounted within the automotive environment, the zenith represents the direction going vertically through the top of the vehicle and the horizon (or horizontal axis) generally runs front to back (forward to aft) of the vehicle. With respect to the integrated cellular quadband antenna  128 , an arrow  218  generally indicates a cellular horizontal polarization axis of the folded inverted F quadband antenna  128 , and an arrow  220  generally indicates a cellular vertical polarization axis of the folded inverted F quadband antenna  128 . 
     The teachings of the present invention are also applicable to other applications having similar functional requirements such as embedded cellular telephones and data terminals, proximity sensors, or any other wireless communications devices. The integrated GPS receiver and cellular transceiver system  100  generally comprises the multilayer PCB substrate  200  and the patch antenna  110  mounted directly on the side  204  of the PCB  200 . The patch antenna  110  may be optimized to receive a 1.575 Ghz RF signal from GPS satellites. The term multilayer PCB generally refers to a PCB having a number of alternating layers of dielectric and conductive printed traces interconnected by conductive vias in a particular pattern that is appropriate for a given electrical circuit (see  FIG. 6 ). 
     An output of the antenna  110  (not shown) may be interconnected to the filter  112  and LNA  114  through interconnecting vias and traces (not shown) on an intermediate layer of the PCB  200  to complete an RF filter system. However, as mentioned above, depending on the implementation of the GPS chipset  102 , one or both of the filter  112  and the LNA  114  may be omitted. A filtered RF signal may be output from the RF filter system to the GPS chipset  102 . All, but a portion of the side  204  of the PCB  200  surrounding the components mounted thereto may be metalized to form a shielding ground plane to improve performance of the system  100 . 
     The RF processing system and digital processing system may be disposed on the side  202  of the PCB  200 . The RF processing system may comprise a RF application specific integrated circuit (ASIC) die, which in one example may be a NAVSTAR ROCS integrated circuit. The RF ASIC die may be mounted directly to the PCB  200  using “chip on board” manufacturing technology. “Chip on board” manufacturing technology is known in the art and comprises mounting an integrated circuit (IC) die directly to a PCB substrate, wirebonding IC contacts to conductive traces printed onto the PCB, and covering the IC and wirebonds with a protective polymer. “Chip on board” manufacturing technology advantageously obviates the need for separately packaging each IC which helps to reduce the physical size and cost of the resulting circuit. 
     Circuitry supporting the RF ASIC may also mounted to the side  202  of the PCB  200  using either “chip on board” or surface mount technology as appropriate. Interconnecting traces and vias present in the PCB  200  interconnect the RF ASIC with the supporting circuitry and the GSM module  104 . Advantageously, the “chip on board” technology removes the use of packaging for the RF ASIC and significantly shortens the length of interconnecting traces through which the analog signals travel. The shortened length reduces the amount of resistive and reactive impedances and, therefore, also reduces signal degradation and loss present in prior art solutions. The RF ASIC and supporting circuitry perform functions that include frequency generation of the local oscillator (LO) and downconversion of the RF signal to an intermediate frequency (IF). The RF processing system outputs an IF signal indicative of the received RF signal. An IF OUT interconnecting trace interconnects the processed RF signal to a digital processing system. 
     The digital processing system may comprise a digital ASIC, which in one example may comprise a NAVSTAR XR7 digital ASIC. The NAVSTAR XR7 digital ASIC may be specifically optimized to receive and process an IF signal from a received GPS RF signal and transmit the processed data to the CAN bus or receive data from the CAN bus, the cellular module  104 , supporting digital circuitry, the program memory  122 , and the data memory  132 . Interconnecting traces and vias present in the PCB  200  interconnect the digital ASIC, the module  104 , supporting digital circuitry, the program memory  122 , and the data memory  132 . The digital ASIC may interconnected to the program and data memories  122  and  132  directly or through the controller  106 , for example, through a plurality of parallel interconnection traces. 
     The digital ASIC samples and digitizes the received IF signal, correlates the data, detects the satellite code, calculates position, velocity and time as a function of the received RF signal and formats the position velocity and time data to be read from the bus. The digital ASIC also reads and interprets bus data and may perform diagnostic self-check of the entire GPS system. An output of the digital ASIC may comprise digital data representing position and velocity of the vehicle in which the patch antenna  110  is disposed. Similar to the side  204  of the PCB  200 , all but a portion of the side  202  of the PCB  200  surrounding the RF processing system, the cellular module components, the digital processing system components, and interconnecting traces may be metalized to form a shielding ground plane  214  that may improve performance of the GPS receiver and cellular transceiver system  100 . In one example, the block  104  may be implemented with, but is not limited to, a LEON-G100/G200 Quad Band GSM/GPRS Data and Voice module (e.g., available from U-blox America, 1902 Campus Commons Drive, Suite 310, Reston, Va. 20191). However, the block  104  may be implemented with other quad band cellular data and voice modules. 
     The PCB  200  may have a ten (10) position connector  134  mounted thereon. The connector  134  supplies power from an external source (e.g., vehicle power supply), and reference potential to the entire GPS receiver and cellular transceiver system  100 . The processed GPS and cellular information may be communicated to and from circuits external to the PCB  200  via the connector  134 . Each digital line (or pin) of the connector  134  may be capacitively filtered (e.g., with chip capacitors positioned between each one of a plurality of signal terminals and the reference potential). Digital data from the system  100  may be communicated to a main processor area (not shown), typically a large PCB, mounted in an automobile that centralizes all of the intelligence functions for the automobile. 
     The GPS and cellular information is generally among many pieces of information received and processed by the main on board computer of the automobile. The connector  134 , as shown in the drawings, is generally chosen for matability with an existing cable assembly in the automobile. Alternatively, other connectors may be equally suitable provided the cable assembly of the automobile is equipped to interface with the connector chosen. Advantageously, any degradation of the digital signal over the cable in the cable assembly can be recovered through signal processing without compromise in the sensitivity of the overall GPS receiver system. 
     Referring to  FIG. 4 , a diagram is shown illustrating the printed circuit board (PCB) substrate  200  of  FIG. 2  with the GPS antenna  110  mounted in an alternate orientation in accordance with the present invention. In one example, the GPS antenna  110  may be mounted perpendicular to an edge of the PCB. The GPS antenna  110  may be separated from the edge of the PCB substrate by the ground plane  210 . The orientation of GPS antenna  110  is generally determined based upon a mounting location of the system  100  within the vehicle. For example, the GPS antenna  110  may be mounted as shown in  FIG. 2  when the system  100  is configured for mounting to a windshield and as shown in  FIG. 3  when the system  100  is configured for mounting elsewhere in the vehicle. In general, the orientation of the GPS antenna  110  is selected such that when the system  100  is mounted in the vehicle the GPS antenna  110  is oriented to maximize a view of the sky. 
     Referring to  FIG. 5 , a diagram is shown illustrating an example geometry and dimensions of the metallization  212  forming the folded inverted F quadband antenna  128  in accordance with an embodiment of the present invention. The folded inverted F quadband antenna  128  may have a first open-circuit stub  220 , a second open circuit stub  222  and a short-circuit stub  224 . The first and second open-circuit stubs may run parallel with the ground plane  214 . The first open-circuit stub  220  may be longer and narrower than the second open-circuit stub  222 . The second open-circuit stub  220  may have a taper at an unconnected end. The short-circuit stub  224  may have a portion aligned with an axis of the first open-circuit stub  220  and a portion folded at a right angle to the axis of the first open-circuit stub  220 . The right angle of the short-circuit stub  224  may be formed with a miter to avoid poor current flow on the short-circuit stub. The folded portion of the short-circuit stub  224  connects to the ground plane  214 . 
     The first open-circuit stub  220  and the short-circuit stub  224  may have a width (e.g., W) of about 0.05 standard units (U). The first open-circuit stub  220  may have a length (e.g., La) of about 2.912 U. The second open-circuit stub  222  may have a length (e.g., Lb) of about 1.525 U and a width (e.g., T 1 ) of about 0.3 U. The integrated folded inverted F quadband antenna  128  may have a height (e.g., H) of about 0.362 U. An input/output  226  of the integrated folded inverted F quadband antenna  128  may have a width (e.g., T 2 ) of about 0.15 U. The input/output  226  of the integrated folded inverted F quadband antenna  128  may be tapered to compensate for differences between an input/output of the cellular transceiver circuitry  104  and the antenna  128 . 
     The dimensions of the antenna  128  are given in the standard unit U because the antenna  128  may be scaled to meet the design criteria of a particular implementation. For example, the metallization  212  forming the folded inverted F quadband antenna  128  is generally laid out for a high temperature, high glass transition temperature (Tg), lead free material dielectric constant substrate (e.g., FR4). However, the antenna  128  may be configured (e.g., scaled) for various substrates (e.g., custom blended), with various dielectric constants, with a scaling factor. The scaling factor may make the antenna  128  larger or smaller. Making the antenna  128  larger increases the efficiency of the antenna, while making the antenna  128  smaller decreases the efficiency with respect to effective aperture. 
     Scaling the antenna  128  does not generally affect the function of the antenna. However, the matching network  140  may need to be implemented when the antenna is scaled smaller. In general, the metallization  212  forming the folded inverted F quadband antenna  128  provides an impressive vertical standing wave ratio (VSWR) for all cellular bands without the matching network  140 . The input/output  226  of the metallization  212  may be connected into a discrete matching network (if implemented), microstrip, or stripline. 
     A vertical aperture of the antenna  128  is generally short but efficient. The low band is folded over, thus having a significant capacitance to ground. The capacitance to ground of the stubs  220  and  222  is generally balanced out by the inductance to ground provided by the stub  224 . However, discrete matching components may be implemented to meet the design criteria of a particular implementation. For example, on an alumina (e.g., K10) substrate, the antenna may be scaled or matched with a matching network. The aperture is generally fixed by the antenna layout. In one example, the best match may be when both the antenna  128  and GSM module  104  have input/output impedances of 50 ohms. As the impedance of the antenna  128  deviates from 50 ohms (e.g., due to scaling), the matching network  140  may be used to improve mismatch losses by bringing the input/output impedances back to a 1:1 ratio. 
     Referring to  FIG. 6 , a diagram is shown illustrating layers of a PCB substrate  250 . The PCB substrate  250  may be implemented as a multilayer structure. In one example, the PCB substrate  250  may be implemented with six metal layers  252 , separated by dielectric layers  254 . The PCB substrate  250  may be used to implement the PCB substrate  200 . In one example, the integrated folded inverted F quadband antenna  128  may be implemented in one of the six metallization layers of the PCB substrate  250 . Interconnecting traces and vias may be implemented in other layers of the PCB substrate  250 . The interconnecting traces and vias may interconnect the various circuits illustrated in  FIG. 1 . Ground planes on different layers may be connected with multiple vias to improve shielding from the GPS signals. 
     Referring to  FIG. 7 , a diagram is shown illustrating an example application of an integrated GPS receiver and cellular transceiver module  100  in accordance with a preferred embodiment of the present invention. In one example, the integrated GPS receiver and cellular transceiver module  100  may be mounted in a vehicle  400 . For example, the integrated GPS receiver and cellular transceiver module  100  may be mounter under a dashboard, against the windshield, or any other place in the vehicle where a view of the sky (e.g., through an RF permeable material) may be obtained by the integrated GPS antenna. The vehicle  400  may further include a system bus  402  (e.g., a CAN bus, etc.), an advanced driver assistance system (ADAS)  404 , and a number of sensors and/or actuators distributed around the vehicle. The term sensor generally refers to a device that generates a signal representative of a sensed condition (e.g., temperature, level, position, speed, etc.). The term actuator generally refers to a device that is configured to control a parameter or object in response to a control signal (e.g., solenoid, heater, lamp, etc.). The sensors and/or accusatory may include, but are not limited to, engine-related devices  406 , front suspension related devices  408 , driver interface devices  410 , drive train related device  412 , rear suspension related devices  414 , and entertainment related systems  416 . 
     The integrated GPS receiver and cellular transceiver module  100 , the sensors and/or the accusatory may feed information to and receive control signals from the ADAS system  404 . The integrated GPS receiver and cellular transceiver module may provide information to the ADAS system  404  which may be used to control various systems of the automobile. The information provided may enhance the performance of the ADAS system  404  in assisting the driver/operator. For example, information from the integrated GPS receiver and cellular transceiver module  100  may provide advanced information on local road conditions, topology, points of interest, etc. that may augment information already stored in the vehicle. The ADAS system  404  may provide information received from the integrated GPS receiver and cellular transceiver module  100  to the driver/operator and/or employ the information to alter one or more vehicle characteristics (e.g., drive train, suspension, steering, braking and stability control assistance, adaptive cruise control, lane departure warning, predictive lighting, curve warning, etc.). 
     The alterations made by the ADAS system  404  may be configured, for example, to increase fuel economy and/or safety of the vehicle. The integrated GPS receiver and cellular transceiver module  100  may further be used to relay information from the ADAS system  404  and/or sensors to a remote site or sites. For example, vehicle performance information along with vehicle location and driving parameters may be relayed to a remote site where the information may be used to update maps and/or driver assistance information. The updated maps and/or driver assistance information may then be sent back to the vehicle to update on-board performance and response parameters. 
     As will be apparent to one of ordinary skill in the relevant art(s), the present invention may be optimized for an integrated GPS receiver and cellular transceiver mounted in other vehicles, in a hand held unit, as well as other applications. 
     While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the invention.

Technology Category: 3