Abstract:
Systems, and apparatus for aligning structures are provided. One of the apparatus includes a first communication module including: a printed circuit board, one or more integrated circuit packages mounted on the printed circuit board, and one or more magnets positioned relative to the one or more integrated circuit packages, wherein the one or more magnets are configured to attractively couple the first communication module to a second communication module positioned in proximity to the first communication module.

Description:
BACKGROUND 
       [0001]    This specification relates to electromagnetic communications. Advances in semiconductor manufacturing and circuit design technologies have enabled the development and production of integrated circuits (ICs) with increasingly higher operational frequencies. In turn, electronic products and systems incorporating high frequency integrated circuits are able to provide greater functionality than previous generations of products. The additional functionality has typically included the processing of increasingly larger amounts of data at increasingly higher speeds. 
         [0002]    Many conventional electronic systems include multiple printed circuit boards (PCBs) upon which ICs are mounted, and through which various signals are routed to and from the ICs. In electronic systems with at least two PCBs and the need to communicate information between the PCBs, a variety of connector and backplane architectures have been developed to facilitate information flow between PCBs. However, conventional connector and backplane architectures typically introduce a variety of impedance discontinuities into the signal path, resulting in a degradation of signal quality or integrity. Connecting to PCBs by conventional means, e.g., signal-carrying mechanical connectors, generally creates discontinuities, requiring expensive electronics to negotiate. Conventional mechanical connectors may also wear out over time, require precise alignment and manufacturing methods, and are susceptible to mechanical jostling. 
       SUMMARY 
       [0003]    In general, one innovative aspect of the subject matter described in this specification can be embodied in an apparatus including a first communication module including: a printed circuit board, one or more integrated circuit packages mounted on the printed circuit board, and one or more magnets positioned relative to the one or more integrated circuit packages, wherein the one or more magnets are configured to attractively couple the first communication module to a second communication module positioned in proximity to the first communication module. 
         [0004]    The foregoing and other embodiments can each optionally include one or more of the following features, alone or in combination. In particular, one embodiment includes all the following features in combination. Each of the integrated circuit packages comprises one or more of a transmitter or a receiver. The first communication module further comprises a respective signal guiding structure surrounding a perimeter formed by each of the one or more integrated circuit packages, wherein each signal guiding structure is configured to insulate the respective integrated circuit package from extraneous signals and to form a channel providing a pathway for data communications. The one or more magnets include a one or more magnets surrounding a portion of each signal guiding structure. The one or more magnets includes a center magnet positioned between a first signal guiding structure and a second signal guiding structure. The one or more integrated circuit packages comprises a transmitter integrated circuit package and a receiver integrated circuit package. The one or more magnets comprise one or more magnets surrounding at least a portion of the transmitter integrated circuit package and one or more magnets surrounding at least a portion of the receiver integrated circuit package. The one or more magnets further comprise a central magnet positioned between the transmitter integrated circuit package and the receiver integrated circuit package. The first communication module is configured to move between an engaged position and a disengaged position. Moving the first communication module between the engaged position and the disengaged position comprises moving the printed circuit board. The printed circuit board is biased to the disengaged position when the one or more magnets are not attracted to magnets of the second communication module. The one or more magnets includes a magnet configured to move between an engaged position and a disengaged position. The magnet is biased to the disengaged position when the one or more magnets are not attracted to magnets of the second communication module. 
         [0005]    In general, one innovative aspect of the subject matter described in this specification can be embodied in an apparatus including a communication module including: one or more integrated circuit packages, one or more magnets, and a movable printed circuit board, wherein the one or more integrated circuit packages and the one or more magnets are positioned relative to the movable printed circuit board such that they move with the movable printed circuit board; and a housing, wherein the movable printed circuit board is positioned relative to the housing such that in an engaged position the printed circuit board is positioned closer to a surface of the housing than in an disengaged position. 
         [0006]    The foregoing and other embodiments can each optionally include one or more of the following features, alone or in combination. In the engaged position, the one or more integrated circuit packages and the one or more magnets are positioned closer to the surface of the housing than in the disengaged position. In the disengaged position a strength of a magnetic field from the one or more magnets at the surface of the housing is less than a specified threshold, and wherein in the engaged position the strength of the magnetic field from the one or more magnets at the surface of the housing is greater than the specified threshold. Movement of the movable printed circuit board is provided by a spring that biases the movable printed circuit board to the disengaged position. Movement of the movable printed circuit board is provided by a magnetic bias structure positioned relative to a surface of the printed circuit board facing opposite the one or more communication modules. Movement of the movable printed circuit board is provided by a compressible material. 
         [0007]    At least one of the one or more integrated circuit packages comprises a transmitter. At least one of the one or more integrated circuit packages comprises a receiver. The communication module includes comprises a first signal guiding structure surrounding a first integrated circuit package and a second signal guiding structure surrounding a second integrated circuit package. The one or more magnets comprise one or more magnets surrounding at least a portion of the first signal guiding structure and one or more magnets surrounding at least a portion of the second signal guiding structure. The one or more magnets further comprise a central magnet positioned between the first signal guiding structure and the second signal guiding structure. The housing is formed of non-metallic material. The housing is formed of a metallic material, the apparatus further comprising one or more one or more non-metallic portions positioned in cutouts of the metallic housing, wherein the one or more non-metallic portions are positioned relative to the one or more integrated circuit packages. One or more galvanic contacts are positioned on the surface of the housing and electronically coupled to the movable printed circuit board. 
         [0008]    In general, one innovative aspect of the subject matter described in this specification can be embodied in an apparatus including a communication module including: one or more integrated circuit packages configured to transmit or receive data, one or more magnets including one or more movable magnets configured to move between an engaged and a disengaged position, and a printed circuit board, wherein the one or more integrated circuit packages and the one or more magnets are positioned relative to the printed circuit board; and a housing, wherein the printed circuit board is positioned relative to the housing such that one or more integrated circuit packages are configured to transmit or receive data through a surface of the housing. 
         [0009]    In general, one innovative aspect of the subject matter described in this specification can be embodied in an apparatus including a communication module including: one or more integrated circuit packages configured to transmit or receive data, one or more magnets, and a printed circuit board, wherein the one or more integrated circuit packages and the one or more magnets are positioned relative to the printed circuit board; and a housing, wherein the printed circuit board is positioned relative to the housing such that one or more integrated circuit packages are configured to transmit or receive data through a surface of the housing. 
         [0010]    In general, one innovative aspect of the subject matter described in this specification can be embodied in an system including a first device comprising: one or more first integrated circuit packages, and one or more first magnets; a second device comprising: one or more second integrated circuit packages, and one or more second magnets; wherein, in response to positioning the first device in a particular relation to the second device, the one or more first magnets and the one or more second magnets provide alignment between the respective first and second one or more integrated circuit packages. 
         [0011]    The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0012]      FIG. 1  is an overhead view of an example IC package. 
           [0013]      FIG. 2  shows a side view representation of an example communication device including an IC package 
           [0014]      FIG. 3  is a side view of an example communication module including a signal guiding structure. 
           [0015]      FIG. 4  is a side view diagram illustrating an example of communication between a transmitter and a receiver. 
           [0016]      FIG. 5  shows a side view diagram illustrating an example of communication between a pair of communication modules. 
           [0017]      FIG. 6  shows a side view diagram illustrating an example of a misaligned pair of transmitters and receivers. 
           [0018]      FIG. 7A  is a cross-sectional diagram of an example first alignment structure in a disengaged position. 
           [0019]      FIG. 7B  is a cross-sectional diagram of the example first alignment structure in an engaged position. 
           [0020]      FIG. 8  is a diagram of an example of the first alignment structure including power transfer. 
           [0021]      FIG. 9  is a cross-sectional diagram of an example second alignment structure. 
           [0022]      FIG. 10  is a diagram of an example of the second alignment structure including power transfer. 
           [0023]      FIG. 11  is a cross-sectional diagram of an example third alignment structure. 
           [0024]      FIG. 12  is a diagram of an example of the third alignment structure including power transfer. 
           [0025]      FIGS. 13A-D  are diagrams illustrating example placements of galvanic contacts. 
           [0026]      FIG. 14  shows an example device housing using the first alignment structure. 
           [0027]      FIG. 15  shows an example device housing using the second alignment structure. 
           [0028]      FIG. 16  shows an example device housing using the third alignment structure. 
           [0029]      FIG. 17  shows example device housings with additional magnets. 
       
    
    
       [0030]    Like reference symbols in the various drawings indicate like elements. 
       DETAILED DESCRIPTION 
       [0031]    This specification describes alignment structures for wireless communication. Wireless communication may be used to provide signal communications between components on a device or may provide communication between devices. 
         [0032]    In one example, tightly-coupled transmitter/receiver pairs may be deployed with a transmitter disposed at a terminal portion of a first conduction path and a receiver disposed at a terminal portion of a second conduction path. The transmitter and receiver may be disposed in close proximity to each other depending on the strength of the transmitted energy, and the first conduction path and the second conduction path may not be contiguous with respect to each other. In some examples, the transmitter and receiver may be disposed on separate circuit carriers positioned with the antennas of the transmitter/receiver pair in close proximity. 
         [0033]    A transmitter and/or receiver may be configured as an integrated circuit (IC) package, in which one or more antennas may be positioned adjacent to a die and held in place by a dielectric or insulating encapsulation or bond material. An antenna may also be held in place by a lead frame substrate. Examples of antennas embedded in IC packages are shown in the drawings and described below. Note that IC packages may also be referred to as simply packages, and are examples of wireless communication units that are also variously referred to as communication units, communication devices, comm-link chips, comm-link chip assemblies, comm-link chip packages, and/or comm-link packages, which may be configured in various ways. For example, IC packages, communication units, communication devices, comm-link chips, comm-link chip assemblies, comm-link chip packages, and/or comm-link packages may each include one or more ICs, chips, or dies and have circuit functionality appropriate for particular applications. 
         [0034]      FIG. 1  shows an example IC package  100 . The IC package  100  includes a die  102  and a transducer  104  providing conversion between electrical and electromagnetic (EM) signals. The IC package  100  may include additional structures, for example, conductive connectors, such as bond wires, electrically connecting the transducer to bond pads connected to a transmitter or receiver circuit included in die  102 . The IC package  100  further includes an encapsulating material  106  formed around at least a portion of the die  102  and/or the transducer  104 . In the example IC package  100 , the encapsulating material  104  completely covers the die  100  and the transducer  104 . 
         [0035]    The die  102  includes any suitable structure configured as a circuit on a suitable die substrate. In some implementations, the die can alternatively be referred to as a chip or an integrated circuit. The die substrate may be composed of any suitable semiconductor material, for example, silicon. In some implementations, the die  102  has a length and a width dimension each of substantially 1.0 mm to about 2.0 mm. The die  102  may be mounted with electrical conductors, such as a lead frame, not shown in  FIG. 1 , electrically coupling the die  102  to one or more external circuits. The IC package  100  can further include a transformer to provide impedance matching between a circuit on the die  102  and the transducer  104 . 
         [0036]    The transducer  104  may be in the form of a folded dipole or loop antenna and is configured to transmit and/or receive electromagnetic signals. In some implementations, the antenna is configured to operate at radio frequencies including radio frequencies in the extremely high frequency (EHF) band of the electromagnetic spectrum, e.g., frequencies from 30 to 300 gigahertz. As shown in IC package  100 , the antenna is separate from the die  102 , but is coupled to the die  102  by suitable conductors, not shown. 
         [0037]    The dimensions of the antenna are determined such that they are suitable for operation in the specified frequency band of the electromagnetic spectrum, e.g., the EHF band. 
         [0038]    In one example, a loop configuration of the antenna can be configured to include a substantially 0.1 mm band of material, laid out in a loop substantially 1.4 mm long and substantially 0.53 mm wide, with a gap of substantially 0.1 mm at the mouth of the loop, and with the edge of the loop approximately 0.2 mm from the edge of die  102 . 
         [0039]    The encapsulating material  106  can be used to assist in holding the various components of IC package  100  in fixed relative positions. The encapsulating material  106  may be formed from a suitable material configured to provide electrical insulation and physical protection for the components of IC package  100 . Additionally, the encapsulating material  106  can be selected from a material that does not impede, or that optimizes passage of, signals to or from the transducer  104 . For example, the encapsulating material  106  can be composed of glass, plastic, or ceramic. The encapsulating material  106  may also be formed in any suitable shape. For example, the encapsulating material  106  may be in the form of a rectangular block, encapsulating all components of the IC package  100  except for any unconnected ends of conductors connecting the die  102  to external circuits. 
         [0040]      FIG. 2  shows a side view representation of an example communication device  200  including an IC package  202  mounted to a PCB  204 . The IC package  202  includes a die  206 , a ground plane  208 , an antenna  210 , and one or more bond wires  212  connecting the die  206  to the antenna  210 . The die  206  and antenna  210  are mounted on a package substrate  214  and encapsulated in an encapsulating material. The ground plane  208  is within the package substrate  214  and is a suitable structure configured to provide an electrical ground for the antenna  210 . The ground plane  208  can extend the entire length of the package substrate  214  or just a portion, in particular, a portion underneath the antenna  210 . The PCB  204  includes a top dielectric layer  216  having a surface  218 . The IC package  202  is mounted to the surface  218  with mounting bumps  220  attached to a metallization pattern (not shown). 
         [0041]    The PCB  204  also optionally includes a layer  222  spaced from dielectric layer  216  made of conductive material forming a ground plane within the PCB  204 . The PCB ground plane may be any suitable structure configured to provide an electrical ground to circuits and components on the PCB  204 . 
         [0042]      FIG. 3  is a side view of an example communication module  300  including a signal guiding structure. As shown in  FIG. 3 , the communication module  300  includes a PCB  302 , an IC package  304 , and a signal guiding structure  306  providing a signal pathway. The communication module  300 , can include a transmitter or receiver for transmitting or receiving signals, e.g., radio frequency signals. 
         [0043]    In particular, the IC package  304  can correspond to the IC packages described above with respect to  FIGS. 1 and 2 . The IC package  304  is mounted on the PCB  302 . For example, the IC package  304  can be mounted to the PCB as described with respect to  FIG. 2 . 
         [0044]    The communication module  300  can be configured to transmit or receive data using radio frequency communication. For example, if the communication module  300  includes a transmitter, the communication module  300  can transmit data, which can then be received by a receiver, e.g., of another communication module. 
         [0045]    The signal guiding structure  306  is configured to aid in directing radio frequency (RF) signals as well as to reduce interference from spurious signals. The signal guiding structure  306  can surround a perimeter of the IC package and extend in the direction of signal transmission and/or reception by a specified amount to provide a channel for emitted or received RF signals. For example, the signal guiding structure  306  can have a height  310  suitable for a particular device including the communication module  300  and that allows the signal guiding structure  306  to be positioned in proximity to a corresponding signal guiding structure of another communication module when used to communicate with another device. The signal guiding structure can be composed of a suitable material that is configured to reduce extraneous signals without disrupting passage of communications along the channel formed by the signal guiding structure  306 . 
         [0046]      FIG. 3  illustrates one IC package  304  mounted to the PCB  302 . However, in other implementations, more than one IC package can be mounted to the same PCB  302 . 
         [0047]    The communication module  300  can be part of a communication system of a device, e.g., a computer, mobile phone, tablet, kiosk, or other device/system. The communication system can be configured to provide wireless communication using one or more IC packages. For example, the communication system can include two IC packages, one configured as a transmitter and the other configured as a receiver. The communication system can be in communication with a storage device. Thus, for example, the communication system can transfer data between the data storage unit and an external device using wireless communication provided by the IC packages. 
         [0048]      FIG. 4  is a side view diagram  400  illustrating an example of communication between a transmitter and a receiver. For example, a user of a first device may wish to exchange data with a second device. The two devices can be positioned in proximity to each other such that the respective communication modules for transmitting and receiving data are aligned and in range of each other. In particular, for EHF frequencies, the devices may need to be very close to each other. For example, the devices may need to be in physical contact to facilitate data communication. 
         [0049]    In  FIG. 4 , a first device includes a first communication module having a transmitter IC package  402  positioned on a first PCB  404 . The transmitter IC package  402  is surrounded by a first signal guiding structure  406  forming a channel. The first signal guiding structure  406  extends to a surface of a first housing  408  of the first device. For example, the first device can be a first mobile phone and the first housing  408  can correspond to the outer case of the first mobile phone. 
         [0050]    A second device includes a second communication module having a receiver IC package  410  positioned on a second PCB  412 . The receiver IC package  410  is surrounded by a second signal guiding structure  414  forming a channel. The second signal guiding structure  414  extends to a surface of a second housing  416  of the second device. For example, the second device can be a second mobile phone and the second housing  416  can correspond to the outer case of the second mobile phone. 
         [0051]    As illustrated by diagram  400 , the first signal guiding structure  406  and the second signal guiding structure  414  are aligned and an outer surface of the first housing  408  and the second housing  416  are in physical contact to provide minimal communication distance and interference. 
         [0052]    A data transmission from the transmitter IC package  402  passes along the first signal guiding structure  406  and the second signal guiding structure  414  to the receiving IC package  410 . 
         [0053]      FIG. 5  shows a side view diagram  500  illustrating an example of communication between a pair of transmitters and receivers. Diagram  500  includes a portion of a first device  502  and a second device  504 . 
         [0054]    The first device  502  includes a first transmitter IC package  506  and a first receiver IC package  508  mounted to a first PCB  510 . Each of the first transmitter IC package  506  and the first receiver IC package  508  is encircled by a respective first signal guiding structure  512 . The first signal guiding structure  512  forms a channel extending to a surface of a first housing  514  of the first device  502 . For example, the first device  502  can be a first mobile phone and the first housing  514  can correspond to the outer case of the first mobile phone. 
         [0055]    The second device  504  includes a second transmitter IC package  516  and a second receiver IC package  518  mounted to a second PCB  520 . Each of the second transmitter IC package  516  and the second receiver IC package  518  is encircled by a respective second signal guiding structure  522 . The second signal guiding structure  522  provides a channel extending to a surface of a second housing  524  of the second device  502 . For example, the second device  502  can be a second mobile phone and the second housing  524  can correspond to the outer case of the second mobile phone. 
         [0056]    As shown in  FIG. 5 , the first signal guiding structures  512  and the second signal guiding structures  522  are substantially aligned on either side of the respective first and second housings  514 ,  524 . The alignment minimizes loss from a data transmission from the first transmitter IC package  506  to the second receiver IC package  518  and from the second transmitter IC package  516  to the first receiver IC package  508 . 
         [0057]    By contrast,  FIG. 6  shows a side view diagram  600  illustrating an example of a misaligned pair of transmitters and receivers. In particular, diagram  600  illustrates the portion of the first device  502  and the second device  504  of  FIG. 5  where the respective signal guiding structures are not aligned. For example, the first device  502  and second device  504  may both be mobile devices. When placed next to each other to communicate data, the devices may not be aligned perfectly such that the signal guiding structures are aligned within a specified tolerance. 
         [0058]    For example, the transmitter and receiver IC packages of each device can operate in the EHF band and require a high degree of alignment to prevent signal degradation or loss. In some implementations, the signal guiding structures are preferably aligned within 0.5 mm. Thus, even a small amount of misalignment can result in signal loss between respective transmitters and receivers of the devices. Additionally, in the example shown in  FIGS. 4-5 , a particular orientation of the first and second devices may be needed to align a respective transmitter with a respective receiver. 
         [0059]    This specification describes alignment structures for aligning the signal guiding structures for data communication. Additionally, the alignment structures can also provide for galvanic and/or wireless transfer of power between devices. In some implementations, the alignment structures are configured to provide alignment in x, y, and z directions, relative to a device surface, of within 0.5 mm. Additionally, the alignment structures can be configured to have a footprint less than or equal 16 mm×8 mm. 
         [0060]    As described below, alignment within the specified tolerance can be facilitated using one or more magnets. The alignment can be achieved while keeping the magnetic field at the surface of each device within a specified threshold, e.g., less than 2000 gauss, when not coupled together. While not necessary, coupling can be performed, e.g., for data communication and/or power transfer. The threshold can be set to reduce the risk of damaging magnetically encoded information positioned near the device, e.g., a credit card with a magnetic strip placed on a phone case. 
         [0061]      FIG. 7A  is a cross-sectional diagram  700  of an example first alignment structure for data communication in a disengaged position.  FIG. 7B  is a cross-sectional diagram  702  of the example first alignment structure for data communication in an engaged position. Having an engaged and disengaged position, as described below, allows stronger magnets to be used to guide and hold alignment when engaged while maintaining the surface magnetic field below the specified threshold when disengaged. 
         [0062]    As shown in  FIGS. 7A and 7B , the alignment structure includes a movable communication module  704 . The movable communication module  704  includes a PCB  706 . Mounted on the PCB  706  are a first IC package surrounded by a first signal guiding structure  708 , a second IC package surrounded by a second signal guiding structure  710 , a center magnet  712 , a first ring magnet  714  surrounding at least a portion of the first signal guiding structure  708 , and a second ring magnet  716  surrounding at least a portion of the second signal guiding structure  710 . The first and second IC packages, PCB  706 , and first and second signal guiding structures  708 ,  710  can be similar to those described above with respect to  FIGS. 1-6 . For example, the first IC package can operate as a transmitter and the second IC package can operate as a receiver. In some other implementations, both the first and second IC package can be of the same type, e.g., both transmitters, both receivers, or one or more of the IC packages can include transceivers configured to operate selectively as either transmitter or receiver. 
         [0063]    In the disengaged position, the movable communication module  704  is recessed from a housing portion  718 . The housing portion  718  can be an insert or an integral portion of a device housing, for example, a case of a mobile device. Thus, in the disengaged position, the movable communication module  704  is recessed so that there is a gap  728  between the communication module  704  and the housing portion  718 . The gap  728  can ensure that the magnetic field at the outer surface of the housing portion  718  is less than the specified threshold. 
         [0064]    The housing portion  718  can be integrated into a housing for a device, for example, part of a case for a mobile device. The housing portion  718  can include a visual identifier  720  to provide a rough alignment to the communication module  704  allowing the device to be positioned in proximity to another communication module, e.g., having a corresponding visual identifier. In some implementations, the visual identifier  720  includes a recess or raised portion of the outer surface to aid in the rough alignment between communication modules. 
         [0065]    The housing portion  718  also includes non-metallic panels  722  and  724 . These non-metallic panels are positioned over the transmission path to or from the IC packages to ensure that data communications pass without interference from the housing portion  718 . For example, if the case of the mobile device is metal, the non-metallic panels prevent the metallic case from interfering with the RF signals of the data communication. In some other implementations, the portion of the device case including the housing portion  718  is non-metallic and therefore the non-metallic panels can be omitted from the housing portion  718 . Regardless of whether the non-metallic panels are present, the particular part of the housing positioned over the transmission path to or from the IC packages is composed of a material configured to allow data transmission and in some cases optimize data transmission. Thus, for example, the housing could be formed of one or more non-metallic materials having different data transmission characteristics as long as the material over the IC transmission path provides for data transmission. 
         [0066]    The center magnet  712  is positioned between the ring magnets  714  and  716 . The center magnet  712  can be shaped, for example, as a rectangular box or cuboid. The ring magnets  714  and  716  can be formed from one or more magnets. For example, a number of magnet segments can be combined to form each ring magnet. Each ring magnet can partially or wholly surround an outside edge of the corresponding signal guiding structure. For example, in some implementations, one or more of the ring magnets can be U-shaped such that they partially surround the signal guiding structures. In some implementations, the sides of the ring magnets perpendicular to the PCB  706  can also be angled off axis from perpendicular and can be non-uniform in thickness. 
         [0067]    In some other implementations, the ring magnets also act as the signal guiding structures such that only the ring magnets are present and positioned similarly to the corresponding ring guiding structures. 
         [0068]    One or more of the magnets can be configured to guide the communication module to an aligned position with an opposing communication module when positioned in proximity to each other (e.g., using the visible identifier  720  as an initial alignment structure). 
         [0069]    In some implementations, one or more of the magnets are configured to align with and attract a corresponding magnet of a second communication module. For example, the first ring magnet  714  can have a top surface, z-axis, corresponding to a north pole and the second ring magnet  716  can have a top surface, z-axis, corresponding to a south pole. When a second, identical communication module, having a particular orientation, is positioned above the first communication module, the north pole of the first ring magnet will attract a south pole of a ring magnet of the second communication module. Similarly the south pole of the second ring magnet will attract a north pole of a ring magnet of the second communication module. 
         [0070]    In some other implementations, one or more of the magnets can be engineered to include a particular alignment pattern of north and south poles along the z-axis. The pattern of magnetic north and south poles are used to program how tightly the magnets attract and hold one another as well as to define how the attraction falls off as the magnets are moved laterally. The patterns can be constructed to form a particular magnetic field so that two magnets will attract most strongly when they are perfectly aligned and repel when shifted laterally, thus guiding the magnets to an aligned position. An example of magnets constructed to have a particular magnetic field pattern is described in the White Paper “Smart Magnets for Precision Alignment” located at http://www.polymagnet.com/media/Polymagnet-White-Paper-3-Smart-Magnets-for-Precision-Alignment.pdf, and incorporated by reference. 
         [0071]    As shown in  FIG. 7B , in the engaged position the communication module  704  is raised such that the magnets and the signal guiding structures are in close proximity to the housing portion  718 . In some implementations, the distance traversed between the engaged and disengaged positions is substantially  1  mm. For example, the signal guiding pathways  708 ,  710  may be raised so that a top edge is in contact with the housing portion  718 . By being in contact with the housing portion  718 , the signal loss due to distance or through the sides of the channel formed by the signal guiding pathways can be reduced. 
         [0072]    Additionally, in the engaged position the magnets are raised so that a maximum magnetic force along the x, y, and z-axis can be applied to corresponding magnets of a second communication module, e.g., of a second device. The maximum magnetic force can be configured to align the signal guiding structures of each communication module for data communication. For example, in some implementations, the magnetic force along a z-axis, e.g., toward another communication module being aligned, is greater than 13 newtons. Although some specific examples of magnetic force are provided here and in the implementations described below, the maximum amount of magnetic force at the housing surface can be variable dependent upon design considerations and types/strengths of magnets used. A minimum magnetic force may be necessary to obtain a desired alignment hold, e.g., 10 newtons, depending on the specific design and whether there is a mechanical hold to provide a shear force that reduces the magnetic force required. 
         [0073]    Various suitable structures can be employed to provide the movement of the communication module  704  from the engaged position to the disengaged position. In some implementations, one or more springs are used to provide a bias force moving the movable communication module  704  to the disengaged position. The force applied by the springs can be less than the magnetic attraction between magnets of opposing communication modules. As a result, when, for example, two devices are placed in proximity to each other, the attraction between the opposing magnets is greater than the force biasing the communication module  704  in the disengaged position, thereby moving the communication module  704  to the engaged position. 
         [0074]    In some other implementations, a magnetic bias is provided below the movable communication module  704 . For example, a base  726  can be positioned below the PCB  706  as part of or as a separate component from the alignment structure. The base  726  can include a metallic portion or layer over a portion of the base  726  that attracts the one or more magnets. As with the force of the one or more springs, the attractive force provided by the magnetic bias can be less than the magnetic attraction between magnets of opposing communication modules such that when, for example, two devices are placed in proximity to each other the magnets attract resulting in the communication module  704  moving to the engaged position. 
         [0075]    In another implementation, a compressible material is positioned between the magnets and the housing portion  718 . The compressible material can be a material, e.g., rubber, that is compressed when the magnets are attracted to magnets of an opposing communication module such that the movable communication module  704  moves to the engaged position. When the opposing communication module is removed, the elastic nature of the compressible material restores the shape of the gasket material pushing the movable communication module  704  to the disengaged position. 
         [0076]      FIG. 8  is a diagram  800  of the first example alignment structure for data communication including power transfer. In particular, diagram  800  shows the housing portion  718  and base  726  for the alignment structure. The housing portion  718  includes the non-metallic panels  722  and  724  positioned over the transmission path to or from the IC packages to ensure that data communications pass without interference from the housing portion  718 . If the housing portion  718  is formed of a non-metallic material, the non-metallic panels  722  and  724  can be omitted. 
         [0077]    The housing portion also includes galvanic contacts  802  and  804 . The galvanic contacts  802  and  804  provide a transfer of electrical energy when placed in contact with a corresponding galvanic contacts of a second alignment structure. For example, a mobile phone having the alignment structure incorporated into the phone housing can position the phone relative to an alignment structure incorporated into another device, e.g., a computer or kiosk. When the alignment structures are positioned in proper alignment, one or more of data transfer and energy transfer can occur. For example, the mobile device can be charged while also transferring data or charged without data transfer. One or more of the galvanic contacts  802  and  804  can be electrically coupled to the PCB of the alignment structure, e.g., PCB  706  of  FIGS. 7A-B . The galvanic contacts  802  and  804  can provide enough power, e.g.,  6  watts, to charge a corresponding device. 
         [0078]      FIG. 9  is a cross-sectional diagram  900  of an example second alignment structure  901 . The alignment structure  901  includes a communication module  905  including a PCB  902 . Mounted on the PCB  902  are a first IC package surrounding by a first signal guiding structure  904 , a second IC package surrounding by a second signal guiding structure  906 , a movable center magnet  908 , a first ring magnet  910  surrounding at least a portion of the first signal guiding structure  904 , and a second ring magnet  912  surrounding at least a portion of the second signal guiding structure  906 . 
         [0079]    The first and second IC packages, PCB  902 , and first and second signal guiding structures  904 ,  906  can be similar to those described above with respect to  FIGS. 1-6 . For example, the first IC package can operate as a transmitter and the second IC package can operate as a receiver. In some other implementations, both the first and second IC package can be of the same type, e.g., both transmitters, or one or more of the IC packages can operate selectively as either transmitter or receiver. 
         [0080]    The center magnet  908  is positioned between the first and second signal guiding structures  904 ,  906 . The center magnet  908  can be shaped, for example, as a rectangular box or cuboid. The center magnet  908  moves between an engaged and a disengaged position. Similar to the first alignment structure described in  FIGS. 7A-7B , the center magnet  908  moves to allow a stronger magnet to be used to guide and hold alignment when the center magnet  908  is engaged while also maintaining the surface magnetic field below a specified threshold level when the center magnet  908  is disengaged. 
         [0081]    In the disengaged position (not shown), the center magnet  908  is recessed from a housing portion  914 . The housing portion  914  can be an insert or an integral portion of a device housing, for example, a case of a mobile device. Thus, in the disengaged position, the center magnet  908  is recessed so that there is a gap between the center magnet  908  and the housing portion  914 . Because of the movable center magnet  908 , stronger magnets can be used to secure alignment while maintaining a specified threshold magnetic field at the surface of the housing portion  914  when the alignment structure is disengaged. In the engaged position, the center magnet  908  is positioned near to or is touching the housing portion  914  such that the gap between the center magnet  908  and the housing portion  914  is reduced or eliminated. The engaged position of the center magnet  908  increases the overall magnetic field strength at the surface of the housing portion  914 , x, y, and z-axis, and provides the attachment alignment between coupled communication modules. 
         [0082]    The movement of the center magnet  908  between the engaged and disengaged position can be provided by a suitable structure that biases the center magnet  908  in the disengaged position when not in proximity to another communication module, for example, using the spring, magnetic bias, or compressible material structures and/or mechanisms described above. 
         [0083]    The ring magnets  910  and  912  can be formed from one or more magnets. For example, a number of magnet segments can be combined to form each ring magnet. Similar to the ring magnets  714  and  716  of  FIGS. 7A-B , each ring magnet can partially or wholly surround an outside edge of the corresponding signal guiding structure. For example, one or more of the ring magnets can be U-shaped such that they partially surround the signal guiding structures. 
         [0084]    One or more of the magnets can be configured to guide the communication module to an aligned position with an opposing communication module when positioned in proximity to each other. The magnets can be similar to the magnets described above with respect to  FIGS. 7A-7B . In particular, one or more of the magnets can be configured with a particular pattern that guides opposing magnets to an aligned position when placed in proximity to each other. 
         [0085]    Because only the center magnet  908  is movable, the overall magnetic force when engaged can be less than the magnetic force of the alignment structure described above with respect to  FIGS. 7A-7B . For example, in the example shown in  FIGS. 7A-7B  the maximum magnetic force, z-axis, in the engaged position can be greater than 13 newtons. By contrast, in some implementations, the maximum magnetic force, z-axis, with the center magnet  908  engaged can be less than 6 newtons. To increase a shear force when two communication modules are coupled together, the alignment structure  901  includes a recess portion  916  and a protrusion portion  918  to provide a mechanical fit between alignment structures. 
         [0086]    The recess portion  916  and the protrusion portion  918  can provide a rough alignment between the first and second signal guiding pathways  904 ,  906  while the ring magnets and center magnet  908  can provide the fine alignment. In some implementations, the recess portion  916  has a recess from a surface of the housing portion  914  of substantially 1 mm. In some implementations, the protrusion portion  918  has a protrusion from a surface of the hosing portion  914  of substantially 1 mm. In some other implementations different heights (or depths) of the protrusions portion and recess portion are possible including heights of less than 1 mm. 
         [0087]    The recess portion  916  and the protrusion portion  918  are positioned to overlay the respective first IC package and the second IC package and formed as part of the housing portion  914 . A portion of the recess portion  916  and the protrusion portion  918  can be formed of a non-metallic material to avoid interference with the data communication passing between signal guiding structures of aligned communication modules. 
         [0088]      FIG. 10  is a diagram  1000  of the second example alignment structure for data communication including power transfer. In particular, diagram  1000  shows the housing portion  914  including the recess portion  916  and protrusion portion  918 . The recess portion  916  includes one or more galvanic contacts  1002  positioned along an interior edge of the recess portion  916 . The protrusion portion  918  includes one or more galvanic contact  1004  positioned along an outer edge of the protrusion portion  918 . 
         [0089]    The galvanic contacts  1002  and  1004  provide a transfer of electrical energy when placed in contact with a corresponding galvanic contacts of a second alignment structure. For example, a mobile phone having the alignment structure incorporated into the phone housing can position the phone relative to an alignment structure incorporated into another device, e.g., a computer or kiosk. When the alignment structures are positioned in proper alignment, one or more of data transfer and energy transfer can occur. For example, the mobile device can be charged while also transferring data or charged without data transfer. One or more of the galvanic contacts  1002  and  1004  can be electrically coupled to the PCB of the alignment structure, e.g., PCB  706  of  FIGS. 7A-B . The galvanic contacts  1002  and  1004  can provide sufficient power, e.g.,  6  watts, to charge a corresponding device. In some implementations, the galvanic contacts are composed of a positive and negative terminal. These terminals can be positioned symmetrically about an axis of the alignment structure. In other implementations, any suitable number of galvanic contacts can be used. 
         [0090]      FIG. 11  is a cross-sectional diagram  1100  of a third example alignment structure  1101  for data communication. The alignment structure  1101  is similar to the alignment structure  901  except that the central magnet  908  is omitted from communication module  1105 . Removing the central magnet results in a more compact footprint for the alignment structure  1101 . However, the removal of the central magnet also results in a reduced magnetic force for aligning corresponding communication modules. For example, in some implementations, the overall magnetic force, z-axis, at the surface of the alignment structure  1101  along a z-axis can be less than  4 . 5  newtons. 
         [0091]    The alignment structure  1101  includes a communication module  1105  including a PCB  1102 . Mounted on the PCB  1102  are a first IC package surrounding by a first signal guiding structure  1104 , a second IC package surrounding by a second signal guiding structure  1106 , a first ring magnet  1108  surrounding at least a portion of the first signal guiding structure  1104 , and a second ring magnet  1110  surrounding at least a portion of the second signal guiding structure  1106 . 
         [0092]    The first and second IC packages, PCB  1102 , and first and second signal guiding structures  1104 ,  1106  can be similar to those described above with respect to  FIGS. 1-6 . The first IC package can operate as a transmitter and the second IC package can operate as a receiver. In some other implementations, both the first and second IC package can be of the same type, e.g., both transmitters, or one or more of the IC packages can operate selectively as either transmitter or receiver. 
         [0093]    The ring magnets  1108  and  1110  can be formed from one or more magnets. For example, a number of magnet segments can be combined to form each ring magnet. Similar to the ring magnets  714  and  716  of  FIGS. 7A-B , each ring magnet can partially or wholly surround an outside edge of the corresponding signal guiding structure. For example, in some implementations, one or more of the ring magnets can be U-shaped such that they partially surround the signal guiding structures. 
         [0094]    One or more of the magnets can be configured to guide the communication module  1105  to an aligned position with an opposing communication module when positioned in proximity to each other. The magnets can be similar to the magnets described above with respect to  FIGS. 7A-7B . In particular, one or more of the magnets can be configured with a particular pattern that guides opposing magnets to an aligned position when placed in proximity to each other. 
         [0095]    Because the overall magnetic force is lower without a center magnet or one or more movable magnets, the alignment structure  1101  includes a recess portion  1112  and a protrusion portion  1114  to provide a mechanical fit between alignment structures and to increase the shear force when two alignment structures are coupled together. 
         [0096]    The recess portion  1112  and the protrusion portion  1114  can provide an initial alignment between the first and second signal guiding pathways  1104 ,  1106  while the ring magnets can provide a finer degree of alignment. The recess portion  1112  and the protrusion portion  1114  can also serve as a visual indicator of the location of the IC packages. In some implementations, the recess portion  1112  has a recess from a surface of a housing portion  1116  of substantially  1  mm. In some implementations, the protrusion portion  1114  has a protrusion from a surface of the hosing portion  1116  of substantially  1  mm. 
         [0097]    The recess portion  1112  and the protrusion portion  1114  are positioned to overlay the respective first IC package and the second IC package and formed as part of the housing portion  1116 . A portion of the recess portion  1112  and the protrusion portion  1114  can be formed of a non-metallic material to avoid interference with the data communication passing between signal guiding structures of aligned communication modules. 
         [0098]      FIG. 12  is a diagram  1200  of the third example alignment structure for data communication including power transfer. In particular, diagram  1200  shows the housing portion  1116  including the recess portion  1112  and protrusion portion  1114 . The recess portion  1112  includes one or more galvanic contacts  1202  positioned along a perimeter of the recess provided by the portion  1112 . The protrusion portion  1114  includes one or more galvanic contacts  1204  positioned along a perimeter of the protrusion provided by the protrusion portion  1114 . 
         [0099]    The galvanic contacts  1202  and  1204  provide a transfer of electrical energy when placed in contact with a corresponding galvanic contacts of a second alignment structure. For example, a mobile phone having the alignment structure incorporated into the phone housing can position the phone relative to an alignment structure incorporated into another device, e.g., a computer or kiosk. When the alignment structures are positioned in proper alignment, one or more of data transfer and energy transfer can occur. For example, the mobile device can be charged while also transferring data or charged without data transfer. One or more of the galvanic contacts  1202  and  1204  can be electrically coupled to the PCB of the alignment structure, e.g., PCB  706  of  FIGS. 7A-B . The galvanic contacts  1202  and  1204  can provide sufficient power, e.g.,  6  watts, to charge a corresponding device. 
         [0100]      FIGS. 13A-D  are diagrams illustrating example placements of galvanic contacts. Other suitable number, placements, and terminal structures can be used. 
         [0101]    In  FIG. 13A , a first galvanic contact  1302  is positioned to surround a portion of a protrusion portion  1304  and a second galvanic contact  1306  is positioned to surround a portion of a recess portion  1308 . In particular, the first galvanic contact  1302  surrounds an outer edge of the protrusion portion  1304  are well as a perimeter of a top of the protrusion portion  1304 . The second galvanic contact  1306  surrounds an inner edge of the recess portion  1308  as well as a portion of a top of the recess portion  1308 , e.g., a portion extending from an edge of each side of the top by a specified amount. Each galvanic contact is split into positive and negative terminals. For example, one-half of the contact forms the positive terminal and one half forms the negative terminal. An insulating material or a spacer can exist between the positive and negative halves. The galvanic connections shown are symmetric around the X axis to ensure that the power terminal of a first device connects to a power terminal of a second device and similarly as to the respective ground terminals. As shown in  FIG. 13A  the positive and negative terminals are symmetric for each galvanic contact, however, in some implementations the orientation of the terminals can be different. 
         [0102]    In  FIG. 13B , a first galvanic contact  1310  is positioned to surround a perimeter of a top of a protrusion portion  1312 . A second galvanic contact  1314  is positioned to surround a perimeter of a top of a recess portion  1316 . Each galvanic contact is split into positive and negative terminals. As shown in  FIG. 13B  the positive and negative terminals are oppositely oriented for each galvanic contact, however, in some implementations the orientation of the terminals can be different. 
         [0103]    In  FIG. 13C , a first galvanic contact  1318  is positioned to surround a perimeter of a top of a recess portion  1320 . A second galvanic contact  1322  is positioned to surround a perimeter of a top of a protrusion portion  1324 . Each galvanic contact forms a respective positive and negative terminal. For example, the first galvanic contact  1318  can be the positive terminal and the second galvanic contact  1322  can be the negative terminal. 
         [0104]    In  FIG. 13D , a first galvanic contact  1326  is positioned to surround an outside edge of a protrusion portion  1328 . A second galvanic contact  1330  is positioned to surround an inside edge of a recess portion  1332 . Each galvanic contact is split into positive and negative terminals. As shown in  FIG. 13D  the positive and negative terminals are symmetrically oriented for each galvanic contact, however, in some implementations the orientation of the terminals can be different. 
         [0105]      FIG. 14  shows an example device housing  1400  using the first alignment structure. In particular, the device housing  1400  can be a metallic housing, e.g., for a mobile device. Because of the metallic housing, non-metallic portions  1402 ,  1404  are included in the housing corresponding to the locations of signal guiding structures. A visual indicator  1406  can be used to provide an initial rough alignment of the communication module using the first alignment structure with another device including another communication module. Alternatively, if a non-metallic material is used for the device housing  1400 , the non-metallic portions  1402  and  1404  can be omitted. 
         [0106]      FIG. 15  shows an example device housing  1500  using the second alignment structure. In particular, the housing  1500  includes a protrusion portion  1502  and a recess portion  1504 . The protrusion portion  1502  and recess portion  1504  correspond to the locations of underlying signal guiding structures. The protrusion portion  1502  and recess portion  1504  provide a visual indicator of the location of the communication module as well as provide a mechanical fit between communication modules. The mechanical fit provides a rough alignment as well as increases shear force needed to separate two devices coupled together, e.g., for data communication. In some implementations, the height of the protrusion portion  1502  above the surface of the device housing  1500  and the depth of the recess portion  1504  below the surface of the device housing  1500  is substantially  0 . 5  mm. In some implementations, non-metallic portions are included when the housing  1500  is formed from a metallic material 
         [0107]      FIG. 16  shows an example device housing  1600  using the third alignment structure. In particular, the housing  1600  includes a protrusion portion  1602  and a recess portion  1604 . The protrusion portion  1602  and recess portion  1604  correspond to the locations of underlying signal guiding structures. Because the third alignment structure does not include a center magnet, a spacing  1606  between the protrusion portion  1602  and the recess portion  1604  is less than that between the protrusion portion  1502  and the recess portion  1504  of  FIG. 15 . 
         [0108]    The protrusion portion  1602  and recess portion  1604  provide a visual indicator of the location of the communication module as well as provide a mechanical fit between communication modules. The mechanical fit provides a rough alignment as well as increases shear force needed to separate two devices coupled together, e.g., for data communication. In some implementations, non-metallic portions are included when the housing  1600  is formed from a metallic material 
         [0109]    The alignment structures described in this specification can be used with communication modules included in various types of devices. These devices can have differing shapes and sizes. In some implementations, one or more additional magnets can be added to the device housing to maintain adequate alignment force between coupled devices. 
         [0110]      FIG. 17  shows example device housings with additional magnets. A first housing  1702  can correspond, for example, to a tablet device. The first housing  1702  includes an alignment structure  1704  including a protrusion portion and a recess portion. The first housing  1702  further includes additional magnets  1706   a - d.  These additional magnets  1706   a - d  can be engaged to help maintain alignment when the first housing  1702  is coupled to devices of different sizes. For example, when coupled to a communication module that is part of another tablet device, all of the additional magnets  1706   a - d  may be engaged with corresponding magnets of the other tablet device. 
         [0111]    By contrast, when coupled to a communication module that is part of a smaller device such as the device illustrated by a second housing  1708 , only the inner two additional magnets  1706   b - c  may be engaged. Finally, when coupled to a communication module of an even smaller device such as the device illustrated by a third housing  1714  (e.g., a mobile phone), none of the additional magnets  1706   a - d  are used. 
         [0112]    The second housing  1708  can correspond, for example, to a large format smartphone. The second housing  1708  includes an alignment structure  1710  including a protrusion portion and a recess portion. The second housing  1708  further includes additional magnets  1712   a - b.  These additional magnets  1712   a - b  can be engaged to help maintain alignment when the second housing  1708  is coupled to devices of different sizes. 
         [0113]    The third housing  1714  can correspond, for example, a smartphone. The third housing  1714  includes magnets as part of an alignment structure  1716  including a protrusion portion and a recess portion. However, the third housing  1714  does not include any additional magnets. 
         [0114]    While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any inventions or of what may be claimed, but rather as descriptions of features specific to particular embodiments of particular inventions. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination. 
         [0115]    Thus, particular embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In certain implementations, multitasking and parallel processing may be advantageous.