Patent Publication Number: US-2023139054-A1

Title: Thermal-Control System Of A Mesh Network Device and Associated Mesh Network Devices

Description:
A mesh network is a network that includes multiple nodes that link together to improve network performance and network accessibility. As an example, a mesh network supporting a wireless local area network (WLAN) may include multiple wireless nodes linking together across an area. Each wireless node, or mesh network device, may provide wireless devices access to the WLAN exchange network information with other mesh network devices. The aggregate functions of the multiple mesh network devices, in general, improve connectivity to the WLAN across the area and improve efficiency of data exchange. 
     In some instances, the mesh network device may be a range-extending mesh network device. The mesh network device may be a small form factor and include multiple electronic subsystems that generate heat. Examples of such electronic subsystems include a printed circuit board (PCB) populated with a variety of integrated circuit (IC) devices. 
     To dissipate heat from electronic subsystems and avoid degradation of the electronic subsystems, a thermal-control system may be used. The design and architecture of an efficient and effective thermal-control system that maintains a small form factor presents multiple challenges. 
     SUMMARY 
     This document describes a thermal-control system that is integrated into a mesh network device and associated mesh-network devices. The thermal-control system, which may include a heat sink, multiple heat spreaders, and a heat shield, is such that heat originating from IC devices, populating a PCB of the mesh network device, may be transferred to a housing component of the mesh network device for external dissipation to maintain a desired thermal profile of the mesh network device. 
     In some aspects, an apparatus is described. The apparatus includes a PCB that is populated with one or more IC devices and that is generally circular about a central axis. The apparatus further includes a thermal-control system to transfer heat generated by the one or more IC devices to a housing component of the apparatus for external dissipation. The thermal-control system includes a heat sink that is generally cylindrical and centered about the central axis. The heat sink includes an interior disk-like body that is substantially orthogonal to the central axis and in thermal contact with at least one of the IC devices. The thermal-control system also includes (i) a first heat spreader that is generally planar and attached to a first surface of the interior disk-like body, and (ii) a heat shield that faces a second, opposite surface of the interior disk-like body. 
     In other aspects, an apparatus is described. The apparatus includes a housing component that has an internal cavity region that is generally concave and symmetrical about a central axis. The apparatus further includes a thermal-control system configured to be positioned within the housing component and transfer heat generated by one or more IC devices to the housing component for external dissipation. 
     The thermal-control system includes a heat sink that is generally cylindrical, is centered about the central axis, and includes a disk-like body. The disk-like body is substantially orthogonal to the central axis, includes a first surface that faces the internal cavity region of the housing component, and is in thermal contact with at least one of the one or more IC devices. The thermal-control system also includes a fan mechanism that is located between the internal cavity region and the first surface of the heat sink. The fan mechanism has one or more blades that rotate about the central axis. The thermal-control system also includes a heat spreader that is (i) generally planar, (ii) attached to the first surface of the heat sink, and (iii) located between the one or more blades and the first surface of the heat sink. 
     The details of one or more implementations are set forth in the accompanying drawings and the following description. Other features and advantages will be apparent from the description, the drawings, and the claims. This Summary is provided to introduce subject matter that is further described in the Detailed Description and Drawings. Accordingly, a reader should not consider the Summary to describe essential features nor limit the scope of the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The details of one or more aspects of a thermal-control system for a mesh network device and associated mesh network devices are described below. The use of the same reference numbers in different instances in the description and the figures may indicate like elements: 
         FIG.  1    illustrates example details including a front isometric view and an exploded view of a mesh network device  102 . 
         FIG.  2    illustrates an exploded isometric view of an example heat sink that may be included in a thermal-control system of a mesh network device. 
         FIG.  3    illustrates an exploded isometric view of a heat spreader and a heat shield that may be included in a thermal-control system of a mesh network device. 
         FIG.  4    illustrates a top plan view of an example PCB that may be included in a mesh network device. 
         FIG.  5    illustrates a bottom plan view of the example PCB from  FIG.  4   . 
         FIG.  6    illustrates an isometric section view of an example mesh network device, including a thermal-control system in accordance with one or more aspects. 
         FIG.  7    illustrates a side section view of an example mesh network device, including an example fan mechanism that may be included as part of a thermal-control system. 
         FIG.  8    illustrates another example heat transfer path that may be effectuated by a thermal-control system of a mesh network device. 
     
    
    
     DETAILED DESCRIPTION 
     This document describes a thermal-control system that is integrated into a mesh network device. The architecture of the thermal-control system is such that heat is conducted from IC devices populating a PCB to other components, for example, a housing component of the mesh network device, for dissipation to maintain a desired thermal profile of the mesh network device. 
     Heat transfer, in general, is energy that is in transit due to a temperature difference. If one or more temperature differences exist across components of a system, such as the mesh network device, heat (e.g., energy in Joules (J)) will transfer from higher temperature zones to lower temperature zones to reduce the temperature differences. There are several mechanisms for heat transfer across the components of the system to reduce temperature differences, including convection, radiation, and conduction. 
     Convection, or heat transfer from a surface due to movement of molecules within fluids such as gases and liquids, may be quantified by equation (1) below: 
         q   conv   =hA ( T   s   −T   ∞ )  (1)
 
     For equation (1), q conv  conv represents a rate of heat transfer from a surface through convection (e.g., in J per second or Watts (W)), h represents a convection heat transfer coefficient (e.g., in W per meter squared (W/m 2 )), T s  represents a temperature of a surface (e.g., in Kelvin (K) or degrees Celsius (° C.)), and T ∞  represents a temperature of a fluid (e.g., in K or ° C.) to which the surface is exposed. The term A represents an area of a surface (e.g., in m 2 ). 
     Radiation, or heat transfer from a surface through electromagnetic radiation, may be quantified by equation (2) below: 
         q   rad   =εA σ( T   s   4   −T   surr   4   (2)
 
     For equation (2), q rad  represents a rate of heat transfer through radiation (e.g., in W), ε represents emissivity (dimensionless), a represents the Stefen-Boltzmann constant (e.g., σ=5.67×10 −8  W/(m 2  K 4 )), T s  represents a temperature of a surface (e.g., in K or ° C.), and T surr  represents a temperature of surroundings of the surface (e.g., in K or ° C.). The term A represents an area of the surface (e.g., in m 2 ). 
     Conduction, or heat transfer through a solid body through atomic and molecular activity, may be quantified by equation (3) below: 
     
       
         
           
             
               
                 
                   
                     q 
                     cond 
                   
                   = 
                   
                     
                       - 
                       kA 
                     
                     ⁢ 
                     
                       dT 
                       dx 
                     
                   
                 
               
               
                 
                   ( 
                   3 
                   ) 
                 
               
             
           
         
       
     
     For equation (3), q cond  represents a rate of heat transfer in a solid material through conduction (e.g., in W), k represents a thermal conductivity of the solid material (e.g., in W/(m·K)), and dT/dx represents a temperature gradient through the solid material (e.g., in K/m or ° C./m). The term A represents a cross-sectional area of the solid material (e.g., in m 2 ). 
     In instances of heat transfer from one physical body to another, through one or more of a convection heat-transfer mechanism, a radiation heat-transfer mechanism, or a conduction heat-transfer mechanism, the physical bodies may be in thermal contact. In some instances, this can include direct physical contact between the bodies or a material (e.g., a thermal interface material, or TIM) located between the bodies, enabling conduction-based heat transfer between the bodies. In other instances, this can include an air gap between the bodies that enables convection-based and/or radiation-based heat transfer between the bodies. 
     A mesh network device may include a thermal-control system that transfers heat using one or more of the heat-transfer mechanisms described above. In general, and in accordance with equations (1) and (2), rates and/or quantities of heat transfer can be varied by increasing or decreasing surface areas for convection and/or radiation within the mesh network device (e.g., increasing or decreasing surface areas of planar heat spreaders). In accordance with equation (3) and within the thermal-control system of the mesh network device, rates and/or quantities of heat transfer can also be varied by introducing, between surfaces, one or more TIMs that have a high thermal conductivity. 
     Through conduction, convection, and radiation heat-transfer mechanisms, as described and quantified by equations (1)-(3) above, the thermal-control system may transfer heat originating from heat-generating electronic devices within the mesh network device to an interior surface of a housing component of the mesh network device. An exterior surface of the housing component may then dissipate the heat to an external environment through convection and/or radiation, effective to prevent degradation of electronic subsystems that may include the heat-generating electronic devices. 
     While features and concepts of the described thermal-control system can be implemented in any number of different environments, apparatuses, and/or various configurations, aspects are described in the context of the following examples. 
       FIG.  1    illustrates example details  100  including a front isometric view and an exploded view of a mesh network device  102 . The mesh network device  102  includes multiple electronic subsystems, including a PCB  104  populated with one or more IC devices. The mesh network device  102  may serve as a node of a wireless mesh network (e.g., a WLAN network conforming to IEEE 802.11 communication protocols (Wi-Fi)). In general, the mesh network device  102  may wirelessly couple other wireless devices (e.g., a wireless phone, a laptop computer) to the wireless mesh network. 
     In general, and while performing operations (e.g., wirelessly coupling the other devices, transferring data), the one or more IC devices populating the PCB  104  may generate an internal heat load  106  (e.g., qi, as measured in W) within the mesh network device  102 . To manage the internal heat load  106  within the mesh network device  102  (e.g., prevent thermal runaway or damage to electronic subsystems of the mesh network device  102 ), the internal heat load  106  may be externally dissipated by elements of the mesh network device  102 , for example, the housing component  108 . 
     The thermal-control system  110  may include multiple elements, including a heat sink  112  and a heat-sink heat spreader  114 . Furthermore, the thermal-control system may include a heat shield  116  and a heat-shield heat spreader  118 . In some instances, the thermal-control system  110  may include additional features that aid in heat transfer, such as one or more TIMs and/or a fan. Furthermore, and depending on configurations of thermal-control system  110 , portions of the internal heat load  106  transferred to the housing component  108  may vary. 
     The heat sink  112  may be generally cylindrical in shape and die-cast from a metal material (e.g., an aluminum material, a magnesium material). The heat-sink heat spreader  114  may be generally circular or elliptical in shape and substantially conform to a shape of a surface of the heat sink  112  on which the heat-sink heat spreader  114  is to be mounted. The heat-sink heat spreader  114  may also be generally planar, formed from one or more sheets of a graphite material. 
     The elements of the thermal-control system  110  (e.g., the heat sink  112 , the heat-sink heat spreader  114 , the heat shield  116 , the heat-shield heat spreader  118 ) conduct, spread, and transfer the internal heat load  106  (e.g., a rate of heat transfer qi in Watts) to the housing component  108  of the mesh network device  102 . In some instances, the heat shield  116  may include a plastic material that impedes heat transfer to a base  120  of the mesh network device, forcing heat to be transferred to the housing component  108 . The housing component  108  may then dissipate the internal heat load  106  (e.g., using a convection heat-transfer mechanism and/or a radiation heat-transfer mechanism) to an external environment. 
     In general, one or more sidewalls of the housing component  108  and/or the base  120  may be varied in thickness and/or length. Such changes in the sidewalls of the housing component and/or the base may change heat transfer characteristics of the thermal-control system  110 . 
     The thermal-control system  110  further maintains a desired thermal profile of the mesh network device  102 . As an example, the conduction, spreading, and transfer of the internal heat load  106  by the thermal-control system  110  may maintain a surface temperature of the housing component  108  at or below a temperature of approximately 67 degrees Celsius (° C.) while the mesh network device  102  is operating in ambient conditions of 25° C. The thermal-control system  110  may also maintain junction temperature of the IC devices populating the PCB  104  at or below different respective temperature thresholds. 
       FIG.  2    illustrates an isometric-view  200  of the heat sink  112  and heat-sink heat spreader  114 . In some instances, the heat sink  112  and the heat-sink heat spreader may be included as part of a mesh network device (e.g., the mesh network device  102  of  FIG.  1   ). 
     As illustrated, the heat sink  112  includes a body  202  that is generally disk-like (e.g., middle region of the heat sink  112 ) extending radially from a central axis  204  to define a perimeter. The body  202  includes a first surface  206  (located under the heat-sink heat spreader  114  in  FIG.  2   ) that is substantially orthogonal to the central axis  204 . The first surface  206  may be generally planar. 
     The heat-sink heat spreader  114  may be attached to the first surface  206  of the body  202  (e.g., using a thermally conductive epoxy). Further, the heat-sink heat spreader  114  may be positioned coaxially with the heat sink  112 , according to the central axis  204 . In some instances, the heat-sink heat spreader  114  may include holes, cutouts, and/or reliefs to avoid interferences with features that may be included as part of the first surface  206 . 
     In some instances, the heat-sink heat spreader  114  may spread and transfer heat to the body  202  using a conduction heat-transfer mechanism. In other instances, the heat-sink heat spreader  114  may spread and transfer heat to a surrounding environment (e.g., an internal cavity region within the housing component  108  of  FIG.  1   ) using a convection heat-transfer mechanism and/or a radiation heat-transfer mechanism. For example, the heat-sink heat spreader  114  may spread and transfer heat in a generally outward direction away from the first surface  206  of the body  202  of the heat sink  112 . 
     The heat-sink heat spreader  114  may include one or more sheets (e.g., layers) of a thermally conductive material such as a graphite material. The heat-sink heat spreader  114  may also include a pressure-sensitive adhesive (PSA) material. Furthermore, different types of materials may be selected to increase or decrease emissivity (ε) and alter radiation characteristics of the heat-sink heat spreader  114 . 
     The heat sink  112  may include one or more fin region(s)  208 . Each fin region  208  may extend from the perimeter of the body  202  in one or more directions that are substantially parallel to the central axis  204 . Furthermore, each fin region  208  may include an interior surface  210  and an opposing exterior surface  212 . In some instances, each fin region  208  may transfer heat to a surrounding environment (e.g., to the housing component  108  of  FIG.  1    or to an internal cavity region within the housing component  108 ) using one or more of a conduction, convection, and/or radiation heat-transfer mechanism. 
     The heat sink may also include a second surface  214  (not visible in  FIG.  2   ). In general, the second surface  214  may be generally planar and opposite the first surface  206 . In some instances, the second surface may include one or more pedestals (protrusions) that aid in establishing thermal contact with heat-generating devices such as IC devices. 
       FIG.  3    illustrates an exploded isometric-view  300  of the heat shield  116  and the heat-shield heat spreader  118  that may be part of a thermal-control system of a mesh network device (e.g., the thermal-control system  110  of the mesh network device  102  of  FIG.  1   ). Also illustrated in  FIG.  3    is the PCB  104 . In some instances, the PCB  104  may be generally circular or elliptical in shape. The PCB  104  may also be generally symmetrical about the central axis  204 . 
     As illustrated, the PCB  104  may include multiple IC devices (e.g., an SoC IC device  302  is identified as an example). In some instances, a respective TIM (e.g., a TIM  304 ) may be located between a respective IC device and a pedestal that may be included as part of a heat sink (e.g., a pedestal that may be protruding from a surface of the heat sink  112  of  FIG.  1   ). As an example, the TIM  304  may be located between the SoC IC device  302  and a respective pedestal of the heat sink (not illustrated in  FIG.  3   ) to create thermal contact between the SoC IC device  302  and the heat sink. 
     In general, the PCB  104  may include multiple IC devices with multiple TIMs. The multiple respective TIMs may, in general, reduce air gaps and/or bond line gaps to provide a thermal conduction path between the multiple IC devices and the heat sink. In some instances, one or more of the multiple respective TIMs may include a thermal pad material. In other instances, one or more of the multiple, respective TIMs may include a thermally conductive gel material or a thermally conductive grease material. 
     An electromagnetic interference (EMI) shield  306  may surround one or more of the multiple IC devices included on the PCB  104 . In some instances, the EMI shield  306  may be positioned between a thermally conductive foam  308  and the PCB  104 . The thermally conductive foam  308  may be configured to interface with a surface or pedestal of the heat sink. Consequently, the thermally conductive foam  308  creates thermal contact between the EMI shield  306  in thermal contact and the heat sink. 
     As illustrated, the heat-shield heat spreader  118  may be located between the heat shield  116  and the PCB  104 , including IC devices that may be populating the PCB  104 . In some instances, a TIM (e.g., a thermal gel material, a thermal grease material) may be located between the heat-shield heat spreader  118  and the PCB  104 . 
     The heat-shield heat spreader  118  may include a generally straight edge  310  that, when assembled as part of a mesh network device (e.g., the mesh network device  102  of  FIG.  1   ), runs parallel to a straight edge  312  of the heat shield  116 . The straight edge  310  may allow clearance within the mesh network device for other elements or features that may be mounted to the PCB  104 , such as one or more Ethernet port(s)  314 . The Ethernet port(s)  314  may extend from the PCB  104  and in a direction that is substantially parallel to the central axis  204 . 
       FIG.  4    illustrates a top plan-view  400  of an example PCB that may be included in a mesh network device (e.g., the PCB  104  of the mesh network device  102  of  FIG.  1   ). The PCB  104  may be a multi-layer PCB that includes a glass-reinforced epoxy laminate material (e.g., FR-4) and multiple layers of electrically conductive traces. The PCB  104  may also be a “double-sided” PCB, where different IC devices may be mounted to opposing surfaces of the PCB  104  using surface-mount (SMT) soldering techniques. In some instances, traces within the multiple layers of the PCB  104  may include a conductive material. For example, traces within the multiple layers of the PCB  104  may include a copper material. The PCB  104  may also include one or more ground planes (e.g., copper ground planes) that may each absorb, spread, and transfer heat within the PCB  104 . 
     A first surface of the PCB  104  (e.g., a first surface  402 ) may be populated with a first set of IC devices  404 . The first surface  402  may face a heat sink of a mesh network device (e.g., the heat sink  112  of the mesh network device  102  of  FIG.  1   ). The first set of IC devices  404  may include, for example, one or more memory IC devices, such as double-data rate dynamic random access memory (DDR DRAM) devices. In some instances, the first set of IC devices  404  may also include the SoC IC device  302  of  FIG.  3   . The first set of IC devices  404  may also include an embedded multimedia card (eMMC) IC device. In some instances, an EMI shield (e.g., the EMI shield  306  of  FIG.  3   ) may surround one or more planar regions  406  of the first surface  402  containing one or more of the first set of IC devices  404 . In some instances, respective TIMs (e.g., one or more of the TIM  304  of  FIG.  3   ) may be located between one or more of the first set of IC devices  404  and a heat sink (e.g., a pedestal included in the heat sink  112  of  FIG.  1   ), creating thermal contact between the first set of IC  404  devices and the heat sink. 
     Each of the first set of IC devices  404  may electrically connect to the PCB  104  using solder connections that result from surface-mount (SMT) manufacturing techniques. In general, the first set of IC devices  404  populating the first surface  402  of the PCB  104 , when operating, may contribute to a heat load (e.g., the internal heat load  106  of  FIG.  1   ) within a mesh network device (e.g., the mesh network device  102  of  FIG.  1   ). 
       FIG.  5    illustrates a bottom plan-view  500  of the PCB from  FIG.  4   , which may be included in a mesh network device (e.g., the PCB  104  of the mesh network device  102  of  FIG.  1   ). A second surface of the PCB  104  (e.g., a second surface  502  that is opposite the first surface  402  of  FIG.  4   ) may face a heat shield of a mesh network device (e.g., the heat shield  116  of the mesh network device  102  of  FIG.  1   ). 
     The second surface  502  of the PCB  104  may be populated with a second set of IC devices  504 . Examples of the second set of IC devices  504  include front end module (FEM) IC devices (e.g., 5 GHz FEM) and radio frequency (RF) IC devices (e.g., 5 GHz RF) that may be associated with wireless communications of a wireless local area network (WLAN). 
     In some instances, one or more of the second set of IC devices  504  may be in thermal contact with a heat spreader (e.g., the heat-shield heat spreader  118  of  FIG.  1   ). In some instances, a TIM (e.g., thermally conductive grease, thermally conductive gel) may be located between one or more of the second set of IC devices  504  and the heat spreader. 
     Each of the second set of IC devices  504  may be electrically connected to the PCB  104  using solder connections that result from SMT manufacturing techniques. In general, the second set of IC devices  404  populating the second surface  502  of the PCB  104 , when operating, may contribute to a heat load (e.g., the internal heat load  106  of  FIG.  1   ) within a mesh network device (e.g., the mesh network device  102  of  FIG.  1   ). 
       FIG.  6    illustrates an isometric section view  600  of the mesh network device  102  in accordance with one or more aspects. The mesh network device  102  includes elements of a thermal-control system (e.g., the thermal-control system  110  of  FIG.  1   ), including the heat sink  112 , the heat-sink heat spreader  114 , the heat shield  116 , and the heat-shield heat spreader  118 . 
     As illustrated, the PCB  104  is located between the heat sink  112  and the heat shield  116 . The first surface  402  of the PCB  104  faces the heat sink  112 , while the second surface  502  of the PCB  104  faces the heat shield  116 . 
     Also illustrated in  FIG.  6    is the housing component  108 . In some aspects, the housing component  108  may function as an antenna radome for one or more antenna(s)  602  located in an internal cavity region  604 . In some instances, the one or more antennas  602  may run substantially parallel to the central axis  204 . The heat-sink heat spreader  114  may include a layer of a polyethylene terephthalate (PET) film with high-emissivity characteristics to efficiently transfer heat (e.g., radiate heat) to the internal cavity region  604 . 
     Furthermore, and in some instances, an air-gap region  606  may separate a perimeter surface of the heat sink  112  from a complementary, interior surface of the housing component  108 . The air-gap region  606  may also separate the interior surface of the housing component  108  from an exterior surface of a fin region that may be part of the heat sink  112  (e.g., the exterior surface  212  of the fin region  208  of  FIG.  2   ). In some instances, a nominal dimension of the air-gap region  606  may measure between approximately 0.5 millimeters (mm) to 2.0 mm, effective to “tune” thermal convection and/or thermal radiation heat-transfer characteristics between the heat sink  112  and the housing component  108 . 
       FIG.  7    illustrates a side section view  700  of the mesh network device  102 , including an example fan mechanism  702  that may be included as part of a thermal-control system (e.g., the thermal-control system  110  of  FIG.  1   ). In general, the fan mechanism  702  may include one or more blades  704  that are configured to rotate about the central axis  204 . In some instances, the one or more blades  704  may be located between the internal cavity region  604  and the first surface  206  of the heat sink  112 . Furthermore, a heat spreader (e.g., the heat spreader  114  of  FIG.  1   ) may be located between the first surface  206  of the heat sink  112  and the one or more blades  704 . The fan mechanism  702 , when activated, may circulate air within the internal cavity region  604 . The circulation of the air within the internal cavity region  604  may, in some instances, improve convection heat-transfer mechanism characteristics within the mesh network device  102 . 
       FIG.  8    illustrates example details  800  of heat-transfer paths within the example mesh network device  102 . The example details  800  include several instances of an isometric sectional view of the mesh network device  102 , including instances  802 ,  804 , and  806 . 
     The top illustration of  FIG.  8    illustrates the instance  802 , including a first heat-transfer path  808  that transfers a portion of an internal heat load (e.g., a portion of the internal heat load  106  originating from multiple IC devices populating the PCB  104  of  FIG.  1   ) through the heat sink  112 . As illustrated, the first heat-transfer path  808  may use conduction, convection, and/or radiation heat-transfer mechanisms to transfer the portion of the internal heat load to the heat sink  112 . The heat sink  112  may then, using convection, conduction, and/or radiation heat-transfer mechanisms, transfer the heat laterally, relative to the central axis, to the housing component  108 . The housing component  108  may then, using convection and/or radiation heat-transfer mechanisms, transfer heat received through the first heat-transfer path  808  to the surrounding environment. 
     The middle illustration of  FIG.  8    provides an enlarged view  810  of the instance  804  within the mesh network device  102 . As illustrated, a second heat-transfer path  812  uses conduction heat-transfer mechanisms to transfer another portion of the internal heat load to the heat sink  112 . As part of the second heat-transfer path  812 , the TIM  304  uses thermal conduction to transfer heat from one of the one or more IC devices  404  to a pedestal of the heat sink  112 . Heat transferred through the second heat-transfer path  812  may “join” with the heat of the first heat-transfer path  808  to be transferred through the housing component  108  to the surrounding environment. 
     The bottom illustration of  FIG.  8    provides the instance  806 . A third heat-transfer path  814  may use convection and/or radiation heat-transfer mechanisms to transfer another portion of the internal heat load (e.g., another portion of the internal heat load  106  originating from multiple IC devices populating the PCB  104 ) to the housing component  108 . The third heat-transfer path  814 , which includes the heat-sink heat spreader  114 , may transfer heat to the internal cavity region  604  through convection and/or radiation heat-transfer mechanisms. The housing component  108  may, using convection and/or thermal heat-transfer mechanisms, transfer heat received through the third heat-transfer path  814  to the surrounding environment. 
     In the following paragraphs, several examples are described: 
     Example 1: an apparatus comprising: a printed circuit board, the printed circuit board generally circular about a central axis and populated with one or more integrated circuit devices; a thermal-control system to transfer heat generated by the one or more integrated circuit devices to a housing component of the apparatus for external dissipation, the thermal-control system comprising: a heat sink, the heat sink generally cylindrical and centered about the central axis, the heat sink including an interior disk-like body that is substantially orthogonal to the central axis and in thermal contact with at least one of the one or more integrated circuit devices; a first heat spreader, the first heat spreader generally planar and attached to a first surface of the interior disk-like body; and a heat shield, the heat shield facing a second surface of the interior disk-like body that is opposite the first surface. 
     Example 2: the apparatus of example 1, wherein the printed circuit board is located between the heat shield and the second surface of the interior disk-like body. 
     Example 3: the apparatus of example 1 or 2, wherein a second heat spreader is located between the heat shield and the printed circuit board. 
     Example 4: the apparatus of example 3, wherein a thermal interface material is located between the second heat spreader and the printed circuit board. 
     Example 5: the apparatus of any of examples 1 to 4, wherein the first surface of the interior disk-like body faces an internal cavity region of the housing component of the apparatus. 
     Example 6: the apparatus of example 5, further including one or more antennas located within the internal cavity region, each of the one or more antennas extending in a direction that is substantially parallel to the central axis. 
     Example 7: The apparatus of any of examples 1 to 6, wherein: the heat sink includes a perimeter surface; and the perimeter surface of the heat sink is separated from a complementary, interior surface of the housing component. 
     Example 8: the apparatus of any of examples 1 to 7, wherein the first heat spreader includes a high-emissivity polyethylene terephthalate film. 
     Example 9: the apparatus of any of examples 1 to 8, further including a thermal interface material, the thermal interface material located between at least one of the one or more integrated circuit devices and the heat sink. 
     Example 10: the apparatus of any of claims  1  to  9 , wherein the heat shield includes a generally straight edge. 
     Example 11: an apparatus comprising: a housing component, the housing component including an internal cavity region that is generally concave and symmetrical about a central axis; a thermal-control system within the housing component, the thermal-control system configured to transfer heat generated by one or more integrated circuit devices to the housing component of the apparatus for external dissipation, the thermal-control system comprising: a heat sink that is generally cylindrical and centered about the central axis, the heat sink including an interior disk-like body that: is substantially orthogonal to the central axis; includes a first surface that faces the internal cavity region; and is in thermal contact with at least one of the one or more integrated circuit devices; a fan mechanism located between the first surface and the internal cavity region, the fan mechanism having one or more blades that rotate about the central axis; and a first heat spreader that is: generally planar; attached to the first surface; and located between the one or more blades of the fan mechanism and the first surface of the heat sink. 
     Example 12: the apparatus of example 11, wherein the first heat spreader includes a high-emissivity polyethylene terephthalate film. 
     Example 13: The apparatus of example 11 or 12, wherein the housing component houses one or more antennas in the internal cavity region of the apparatus, the one or more antennas extending in a direction that is substantially parallel to the central axis. 
     Example 14: the apparatus of any of examples 11 to 13, further comprising a heat shield that faces a second surface of the interior disk-like body, the second surface opposite the first surface. 
     Example 15: the apparatus of example 14, further comprising a printed circuit board that includes the one or more integrated circuit devices, the printed circuit board generally circular and located between the heat shield and the second surface of the interior disk-like body. 
     Although techniques using and apparatuses for a thermal-control system of a mesh network device and associated mesh network devices are described, it is to be understood that the subject of the appended claims is not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as example ways in which a thermal-control system of a mesh network device and associated mesh network devices can be implemented.