Abstract:
A modular device system is provided having a base portable electronic communication device. The base portable electronic communication device has a display side and a reverse side, and one or more antennas being located along one of the device edges. A ground element on the reverse side of the housing is adjacent to the antennas and is grounded to the chassis. A multi-pin connector array on the same side is located adjacent to the ground element and the ground element lies between the connector array and the antennas. The ground element is configured to contact a mating ground element on an add-on module when the module is mated to the base portable electronic communication device.

Description:
TECHNICAL FIELD 
     The present disclosure is related generally to mobile communication devices, and, more particularly, to a system and method for mitigating unwanted RF coupling in a modular portable device system. 
     BACKGROUND 
     High-frequency electronic signals are useful with respect to increasing data rates and hence device response times. However, as data rates increase, the inventors have discovered that coupling between high-frequency lines or connectors and nearby antennas also increases. The effect is two-way, in that signals associated with high frequency antennas may also couple into nearby high-frequency lines or connectors. 
     While the present disclosure is directed to a system that can eliminate certain shortcomings noted in or apparent from this Background section, it should be appreciated that such a benefit is neither a limitation on the scope of the disclosed principles nor of the attached claims, except to the extent expressly noted in the claims. Additionally, the discussion in this Background section is reflective of the inventors&#39; own observations, considerations, and thoughts, and is not intended to catalog or summarize any item of prior art. As such, the inventors expressly disclaim this section as admitted or assumed prior art. Moreover, the identification or implication herein of a desirable course of action reflects the inventors&#39; own observations and ideas, and therefore cannot be assumed to indicate an art-recognized desirability. 
     SUMMARY 
     In keeping with an embodiment of the disclosed principles, a modular device system is provided having a base portable electronic communication device with a chassis and housing and one or more antennas located along one of the top, bottom and side edges of the device. A ground element on the reverse side of the housing is adjacent to the one or more antennas, and a multi-pin connector array is adjacent to the ground element such that the ground element lies between the connector array and the antennas. 
     In another embodiment, a modular device connection system is provided for physically and electrically connecting an electronic module to a portable electronic communication device. A ground element is provided adjacent to the device antennas, the ground element being grounded to a chassis of the device. A multi-pin connector array is located adjacent to the ground element such that the ground element lies between the connector array and the one or more antennas. 
     In yet another embodiment, a modular electronic device system is provided having a portable electronic device with a device ground element on the device housing adjacent to one or more device antennas. The device ground element is grounded to the device chassis, and lies between the antennas and a device multi-pin connector array. Similarly, a mating electronic module has a multi-contact module ground element providing a module ground. Similarly, a module multi-pin module connector array is provided and the multi-contact module ground element and module multi-pin module connector array are configured and located to electrically connect to the device ground element and the device multi-pin connector array respectively when the electronic module is mated to the portable electronic device. 
     Other features and aspects of embodiments of the disclosed principles will be appreciated from the detailed disclosure taken in conjunction with the included figures. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       While the appended claims set forth the features of the present techniques with particularity, these techniques, together with their objects and advantages, may be best understood from the following detailed description taken in conjunction with the accompanying drawings of which: 
         FIG. 1  is a simplified schematic of an example configuration of device components with respect to which embodiments of the presently disclosed principles may be implemented; 
         FIG. 2  is view of a first device and a second device, showing the back of the first device and the back of the second device in accordance with an embodiment of the disclosed principles; 
         FIG. 3  is a side view of a phone and module in accordance with an embodiment of the disclosed principles; 
         FIG. 4  is a subassembly view showing a portion of the rear housing in top and bottom views in accordance with an embodiment of the disclosed principles; 
         FIG. 5  is a simplified view of a connector arrangement for connecting to a continuous debar in accordance with an embodiment of the disclosed principles; 
         FIG. 6  is a data plot showing the isolation effect, in dB, of employing a debar of 44 mm in a modular configuration in accordance with an embodiment of the disclosed principles; and 
         FIG. 7  is a data plot showing the isolation effect, in dB, of employing a debar of 27 mm in a modular configuration in accordance with an embodiment of the disclosed principles. 
     
    
    
     DETAILED DESCRIPTION 
     Before presenting a fuller discussion of the disclosed principles, an overview is given to aid the reader in understanding the later material. As noted above, 
     Within the modular concept conceived by the inventors, an external unit (“mod” or “module”) is configured to connect to a base unit (e.g., a mobile phone) through multiple exposed connectors to enhance user experience. Modules may provide enhanced imaging, entertainment, presentation and other functionality. In an embodiment, the phone may also connect to docks, computers, tablets, etc. using the same connector configuration 
     The communication between the phone and the module may happen at varying speeds, from DC up to 5 Gbps or higher. These high speed connectors are in close proximity of the transmit and receive antennas of the device. Hence attaching a mod to the device may generate noise from the exposed connectors, which elevates a noise floor used to separate noise from signal, and thus may lead to desensitization of the phone&#39;s cellular receivers. This phenomenon may be referred to herein as “desense.” In addition, interference from the cellular transmit antennas may cause the devices to throttle data transfer through the exposed mod connectors due to reverse desense. 
     Embodiments of the disclosed principles mitigate desensitization of the phone RF/Antenna system from unshielded high speed pin connections between phone and mod by implementing a ground wall is linked across the phone and the mod. This may be implemented by placing a metal bar (sometimes referred to herein as a “debar’) on the phone face, with the debar being tied to the reference ground on the phone&#39;s PCB (printed circuit board). The debar may extend beyond the width of the connector pin array, and in an embodiment extends outside of the width of the connector pin array by about 8 mm on either side. It will be appreciated that the length of the debar may be longer or shorter depending on specific design features in a given instance. 
     The debar separates the mod connector array from the nearest antennas, e.g., the bottom antennas. A similarly metal bar is tied to the mod&#39;s PCB. In a further embodiment, these two bars are connected to each other through an array of pogo pins (e.g., about 8 of them, although a lesser or greater number may be used depending on specific design features in a given instance. It will be appreciated that with respect to the connector array, it is not important which device includes which of the pogo pins and debar, or which contains which of the electrical connector types. As will be shown later, use of the debar system significantly reduces interference and thus reduces desense. 
     Additionally, a metal plate may be placed over the connector array with holes located to allow connector pins to pass through for additional isolation. The metal plate is electrically connected via solder or conductive adhesive to the AMP PCB ground chassis, and may conductively contact the phone metal backing when the AMP is attached to phone, thereby filling the non-metal gap around the connector pins with shielding metal, but not forming an overlapping ground shield into the phone (unlike USB or HDMI connectors), thereby maintaining ID integrity of the back of the phone. 
     With this overview in mind, and turning now to a more detailed discussion in conjunction with the attached figures, the techniques of the present disclosure are illustrated as being implemented in a suitable computing environment. The following device description is based on embodiments and examples of the disclosed principles and should not be taken as limiting the claims with regard to alternative embodiments that are not explicitly described herein. Thus, for example, while  FIG. 1  illustrates an example mobile device within which embodiments of the disclosed principles may be implemented, it will be appreciated that other device types may be used. 
     The schematic diagram of  FIG. 1  shows an exemplary component group  110  forming part of an environment within which aspects of the present disclosure may be implemented. In particular, the component group  110  includes exemplary components that may be employed in a device corresponding to the first device or phone, and the second device. It will be appreciated that additional or alternative components may be used in a given implementation depending upon user preference, component availability, price point, and other considerations. 
     In the illustrated embodiment, the components  110  include a display screen  120 , applications (e.g., programs)  130 , a processor  140 , a memory  150 , one or more input components  160  (user input receiver) such as speech and text input facilities, and one or more output components  170  such as text and audible output facilities, e.g., one or more speakers. In an embodiment, the input components  160  include a physical or virtual keyboard maintained or displayed on a surface of the device. In various embodiments motion sensors, proximity sensors, camera/IR sensors and other types of sensors may be used to collect certain types of input information such as user presence, user gestures and so on. 
     The processor  140  may be any of a microprocessor, microcomputer, application-specific integrated circuit, and like structures. For example, the processor  140  can be implemented by one or more microprocessors or controllers from any desired family or manufacturer. Similarly, the memory  150  may reside on the same integrated circuit as the processor  140 . Additionally or alternatively, the memory  150  may be accessed via a network, e.g., via cloud-based storage. The memory  150  may include a random access memory (i.e., Synchronous Dynamic Random Access Memory (SDRAM), Dynamic Random Access Memory (DRAM), RAMBUS Dynamic Random Access Memory (RDRM) or any other type of random access memory device or system). Additionally or alternatively, the memory  150  may include a read only memory (i.e., a hard drive, flash memory or any other desired type of memory device). 
     The information that is stored by the memory  150  can include program code associated with one or more operating systems or applications as well as informational data, e.g., program parameters, process data, etc. The operating system and applications are typically implemented via executable instructions stored in a non-transitory computer readable medium (e.g., memory  150 ) to control basic functions of the electronic device. Such functions may include, for example, interaction among various internal components and storage and retrieval of applications and data to and from the memory  150 . 
     Further with respect to the applications  130 , these typically utilize the operating system to provide more specific functionality, such as file system services and handling of protected and unprotected data stored in the memory  150 . Although some applications may provide standard or required functionality of the user device  110 , in other cases applications provide optional or specialized functionality, and may be supplied by third party vendors or the device manufacturer. 
     Finally, with respect to informational data, e.g., program parameters and process data, this non-executable information can be referenced, manipulated, or written by the operating system or an application. Such informational data can include, for example, data that are preprogrammed into the device during manufacture, data that are created by the device or added by the user, or any of a variety of types of information that are uploaded to, downloaded from, or otherwise accessed at servers or other devices with which the device is in communication during its ongoing operation. The device  110  also includes a camera module  180 , which is linked to a device camera. 
     In an embodiment, a power supply  190 , such as a battery or fuel cell, is included for providing power to the device  110  and its components. All or some of the internal components communicate with one another by way of one or more shared or dedicated internal communication links  195 , such as an internal bus. 
     In an embodiment, the device  110  is programmed such that the processor  140  and memory  150  interact with the other components of the device  110  to perform certain functions. The processor  140  may include or implement various modules and execute programs for initiating different activities such as launching an application, transferring data, and toggling through various graphical user interface objects (e.g., toggling through various display icons that are linked to executable applications). 
     Applications and software reside on a tangible non-transitory medium, e.g., RAM, ROM or flash memory, as computer-readable instructions. The device  110 , via its processor  140 , runs the applications and software by retrieving and executing the appropriate computer-readable instructions. 
     Turning to  FIG. 2 , this figure illustrates a simplified view of the phone  200  and the module  201 , showing the back  203  of the phone  200  and the mating front  205  of the module  201  in accordance with an embodiment of the disclosed principles. In the illustrated example, each device  200 ,  201  includes a connector array  207 ,  209 . Although each connector array  207 ,  209  is shown as a 16-pin connector array, it will be appreciated that other numbers of pins may be used. Although not detailed in the figure, one of the connector arrays  207 ,  209  will typically include spring-loaded male pins while the other  207 ,  209  will typically include corresponding female sockets or contacts. The grounded debar discussed above can be seen in  FIG. 2  as element  217 , and the mating pogo connectors as element  213 . The phone  200  also includes one or more antennas  231 ,  233 . 
     In the illustrated embodiment, an alignment socket  211  is included within the connector array  207  on the phone  200 , for mating with a matching alignment pin  215  on the module  201 . A third alignment point is provided by a camera protrusion  219  on the phone  200 , which is configured and located to fit with a mating circular opening  221  in the module  201 . In an embodiment, the camera protrusion  219  contains the main camera of the device  200  as well as one or more flash LEDs. In an embodiment, the camera protrusion  219  also includes a laser range-finder for faster focus of the main camera. 
     As noted above, although other camera protrusion shapes are usable and are contemplated herein, a circular shape will be used for the sake of example. Depending upon tolerances in a given implementation, a non-circular camera protrusion may provide a degree of rotational alignment as well and may limit or eliminate the need for other alignment features. 
     In an embodiment, a set of magnets  223 ,  225 ,  227 ,  229  is embedded in the front of the module  201 . These magnets  223 ,  225 ,  227 ,  229  may be retained on an inner surface of this cosmetic sheet. These magnets may be encased in a steel shroud such that the magnetic field is focused to one side of the magnet assembly rather than extending to both sides. In an embodiment, these magnets  223 ,  225 ,  227 ,  229  attract the steel surface of the back  203  of the phone  200  so as to hold the devices  200 ,  201  together once the devices  200 ,  201  are in close proximity. The magnets  223 ,  225 ,  227 ,  229  may be of ceramic, neodymium or other type. 
       FIG. 3  is a side view of the phone  200  and the module  201  in accordance with an embodiment of the disclosed principles. As briefly shown in the side view of  FIG. 3 , when the phone  200  and the module  201  are docked together, the camera protrusion  219  fits into the mating opening  221  in the module  201 . In addition, the contact array  207  of the phone  200  mates with the contact array  209  of the module  201  in this configuration. 
     Ideally the combined device acts as one, using the connections provided by the mating contact arrays  207 ,  209 . In particular, the contact arrays  207 ,  209  are used in various embodiments to exchange data, commands, power, control signals and so on. 
       FIG. 4  is a subassembly view showing a portion of the rear housing  401  in top and bottom views, in an embodiment wherein the debar  217  is ski-booted/toed into the rear housing  401  to have multiple direct contact points grounding to the main PCB. 
       FIG. 5  is a detail view of the pogo connectors  213  and a connector array shroud  501  in accordance with an embodiment of the disclosed principles. As can be seen, the pogo connectors  213  are positioned to contact the debar  217  ( FIG. 2 ) when the phone  200  and module  201  are mated together. The grounded shroud  501  partially surrounds each connector pin in the array  209  ( FIG. 2 ), providing additional shielding. 
     As noted above, the use of a debar, as described herein or similar, can significantly increase isolation of the antennas and the pins of the connector arrays.  FIG. 6  is data plot showing the isolation effect, in dB, of employing a debar of 44 mm in a modular configuration as described herein. In particular, a first plot  601  shows the original level of isolation and a second plot  603  shows the level of isolation achieved using the debar. As can be seen, use of the debar increases isolation by more than 5 dB throughout the range from about 700 MHz to about 870 MHz. 
       FIG. 7  is data plot showing the isolation effect, in dB, of using a debar of a different length than that used in the plot of  FIG. 6 , namely a debar of 27 mm. The first plot  701  shows the original level of isolation and a second plot  703  shows the level of isolation achieved using the debar of 27 mm. In this case, the isolation effect is worse than with the longer debar. 
     It will be appreciated that a system and method for improved mobile phone isolation for a modular system have been described herein. However, in view of the many possible embodiments to which the principles of the present disclosure may be applied, it should be recognized that the embodiments described herein with respect to the drawing figures are meant to be illustrative only and should not be taken as limiting the scope of the claims. Therefore, the techniques as described herein contemplate all such embodiments as may come within the scope of the following claims and equivalents thereof.