Abstract:
An electronic device is within a housing that has an aperture through an enclosure surface of the housing. A ferrite block is attached to an edge of the aperture, thus transforming electromagnetically-induced current next to the aperture into heat in order to reduce a voltage across the aperture, thereby suppressing aperture edge emissions.

Description:
BACKGROUND 
     The present disclosure relates to the field of equipment housing, and specifically to electronic equipment housing. Still more particularly, the present disclosure relates to suppressing aperture edge emissions in electronic equipment housings. 
     BRIEF SUMMARY 
     An electronic device is within a housing that has an aperture through an enclosure surface of the housing. A ferrite block is attached to an edge of the aperture, thus transforming electromagnetically-induced current next to the aperture into heat in order to reduce a voltage across the aperture, thereby suppressing aperture edge emissions. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  depicts an exemplary computer which may be utilized in one embodiment of the present disclosure; 
         FIG. 2  illustrates an aperture passing through an enclosure surface of a housing of an electronic device; 
         FIG. 3  depicts ferrite blocks mounted along edges of the aperture shown in  FIG. 2 ; 
         FIG. 4  illustrates a pathway of electromagnetically-induced current being directed through one of the ferrite blocks shown in  FIG. 3 ; and 
         FIG. 5  is a high level flow chart of one or more exemplary steps taken by a computer to fabricate a housing for an electronic device. 
     
    
    
     DETAILED DESCRIPTION 
     As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon. 
     Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. 
     A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. 
     Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including, but not limited to, wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing. 
     Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The program code may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). 
     Aspects of the present invention are described below with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
     These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks. 
     The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
     With reference now to the figures, and in particular to  FIG. 1 , there is depicted a block diagram of an exemplary computer  102 , which may be utilized by the present invention. Note that some or all of the exemplary architecture, including both depicted hardware and software, shown for and within computer  102  may be utilized by software deploying server  150 . 
     Computer  102  includes a processor  104  that is coupled to a system bus  106 . Processor  104  may utilize one or more processors, each of which has one or more processor cores. A video adapter  108 , which drives/supports a display  110 , is also coupled to system bus  106 . In one embodiment, a switch  107  couples the video adapter  108  to the system bus  106 . Switch  107  is a switch, preferably mechanical, that allows the display  110  to be coupled to the system bus  106 , such that display  110  is functional only upon execution of instructions (e.g., housing fabrication program—HFP  148  described below) that support the processes described herein. 
     System bus  106  is coupled via a bus bridge  112  to an input/output (I/O) bus  114 . An I/O interface  116  is coupled to I/O bus  114 . I/O interface  116  affords communication with various I/O devices, including a keyboard  118 , a mouse  120 , a media tray  122  (which may include storage devices such as CD-ROM drives, multi-media interfaces, etc.), and a computer controlled manufacturing machine (CCMM)  124 , which is capable of punching holes into an enclosure surface of a housing for electronic equipment, affixing ferrite to edges of that hole, etc. as described herein. While the format of the ports connected to I/O interface  116  may be any known to those skilled in the art of computer architecture, in a preferred embodiment some or all of these ports are universal serial bus (USB) ports  126 . 
     As depicted, computer  102  is able to communicate with a software deploying server  150  via network  128  using a network interface  130 . Network  128  may be an external network such as the Internet, or an internal network such as an Ethernet or a virtual private network (VPN). 
     A hard drive interface  132  is also coupled to system bus  106 . Hard drive interface  132  interfaces with a hard drive  134 . In a preferred embodiment, hard drive  134  populates a system memory  136 , which is also coupled to system bus  106 . System memory is defined as a lowest level of volatile memory in computer  102 . This volatile memory includes additional higher levels of volatile memory (not shown), including, but not limited to, cache memory, registers and buffers. Data that populates system memory  136  includes computer  102 &#39;s operating system (OS)  138  and application programs  144 . 
     OS  138  includes a shell  140 , for providing transparent user access to resources such as application programs  144 . Generally, shell  140  is a program that provides an interpreter and an interface between the user and the operating system. More specifically, shell  140  executes commands that are entered into a command line user interface or from a file. Thus, shell  140 , also called a command processor, is generally the highest level of the operating system software hierarchy and serves as a command interpreter. The shell provides a system prompt, interprets commands entered by keyboard, mouse, or other user input media, and sends the interpreted command(s) to the appropriate lower levels of the operating system (e.g., a kernel  142 ) for processing. Note that while shell  140  is a text-based, line-oriented user interface, the present invention will equally well support other user interface modes, such as graphical, voice, gestural, etc. 
     As depicted, OS  138  also includes kernel  142 , which includes lower levels of functionality for OS  138 , including providing essential services required by other parts of OS  138  and application programs  144 , including memory management, process and task management, disk management, and mouse and keyboard management. 
     Application programs  144  in computer  102 &#39;s system memory (as well as software deploying server  150 &#39;s system memory) include a housing fabrication program (HFP)  148 . HFP  148  includes code for fabricating the housing described herein, including that described in  FIGS. 2-4 , utilizing a process described in  FIG. 5 . In one embodiment, computer  102  is able to download HFP  148  from software deploying server  150 , including in an on-demand basis, wherein the code in HFP  148  is not downloaded until needed for execution to define and/or implement the improved enterprise architecture described herein. Note further that, in one embodiment of the present invention, software deploying server  150  performs all of the functions associated with the present invention (including execution of HFP  148 ), thus freeing computer  102  from having to use its own internal computing resources to execute HFP  148 . 
     The hardware elements depicted in computer  102  are not intended to be exhaustive, but rather are representative to highlight essential components required by the present invention. For instance, computer  102  may include alternate memory storage devices such as magnetic cassettes, digital versatile disks (DVDs), Bernoulli cartridges, and the like. These and other variations are intended to be within the spirit and scope of the present invention. 
     Referring now to  FIG. 2 , an enclosure surface  202  of a housing (not shown) is depicted. Note that the term “enclosure surface” defines any surface of the housing, and thus can be a top, bottom, left side, right side, etc. of the housing. The housing may be for any electronic equipment that is susceptible to, or that generates, electromagnetism. While enclosure surface  202  is planar in order to provide the maximum improvement of the issues described herein, enclosure surface  202  may be curved, angular, irregularly shaped, etc. Whatever shape is used for enclosure surface  202 , in one embodiment enclosure surface  202  is solid metal to provide the maximum improvement of the issues described herein. In all embodiments, enclosure surface  202  is metallic, and is therefore susceptible to electromagnetically-induced voltages, currents and secondary fields. 
     The housing may be for any type of equipment that emits or is sensitive to electromagnetically-induced voltages. For example, the housing may be for a drawer containing multiple server blades; a stand-alone computer; a piece of electronic test equipment, etc. Such devices often require openings that pass through the housing, in order to allow cooling air to pass through, to allow a user to visually see gauges, warning lights, etc. within the housing, etc. However, such openings, such as aperture  204  shown in  FIG. 2 , create a problem when the housing is exposed to electromagnetic radiation. More specifically, when electromagnetism, which has a wavelength that is larger than the opening of the aperture  204 , strikes the enclosure surface  202 , a voltage is induced across the aperture  204 . This voltage is the result of voltage-resultant current passing from one end ( 201 ) of the enclosure surface  202  to another end ( 203 ) of the enclosure surface  202 . The aperture  204  prevents a smooth flow of current from end  201  to end  203 , since the current must flow about the edges of aperture  204 . This causes a voltage drop across the aperture  204 , which can result in secondary fields and inductions, since aperture  204  acts as a slot antenna. In order to avoid these issues, ferrite is mounted around the edges of aperture  204 . In order to mount such ferrite, slots  206   a - d  are cut into the enclosure surface  202 . These slots  206   a - d  result in ferrite mounts  208   a - d . Ferrite mounts  208   a - d  are not themselves made of ferrite, but rather are remaining portions of the enclosure surface  202  to which ferrite blocks (described herein) are affixed. Impedance holes  210   a - d  are also cut into enclosure surface  202 . As described herein, these impedance holes  210   a - d  force electromagnetically-induced current to flow into one or more of the ferrite mounts  208   a - d  and the ferrite mounted thereon. Note that while each of the sets of impedance holes  210   a - d  are depicted as aligning in straight lines in the figures, each set of impedance holes  210   a - d  may be configured to be curved, angled, or of a shape designed to raise the impedance to current flowing around the ferrite mounted on ferrite mounts  208   a - d . The present disclosure thus permits open holes (e.g., aperture  204 ) to be cut into housings, rather than using openings that are covered by mesh, perforations, etc. 
     Referring now to  FIG. 3 , ferrite blocks  302   a - d  are respectively mounted to ferrite mounts  208   a - d . This mounting creates a physical and electrical connection between the ferrite blocks  302   a - d  and their respective ferrite mounts  208   a - d . The ferrite blocks  302   a - d  are made of ferrite, which gives them the ability to convert electrical current into heat. This conversion is accomplished by internal magnetic areas within the ferrite block  302   a - d  attempting to realign themselves when they consume electrical current. However, the solid nature of the ferrite prevents such realignment, resulting in the generation of heat while the ferrite is consuming the electrical current. While ferrite blocks  302   a - d  are depicted as elongated blocks, ferrite blocks  302   a - d  may be any shape that permits electromagnetically-induced current to be transformed into heat. 
     With reference now to  FIG. 4 , assume that enclosure surface  202  has been impinged with (exposed to) electromagnetism that has a wavelength that is greater than the opening created by aperture  204 . This impingement results in an electromagnetically-induced current, which begins as current  404   a . Current  404   a  attempts to go around aperture  204 , resulting in a split into currents  404   b  and  404   c . However, current  404   c  is prevented from passing across the resistance caused by impedance holes  210   d . Thus, the current  404   a  is directed as current  404   b  into the ferrite block  302   d . Although a trace current  404   d  exits from ferrite block  302   d , most of current  404   b  is consumed and converted into heat by ferrite block  302   d . This prevents a voltage drop across aperture  204 , and thus prevents any secondary fields, currents, etc. from forming around the aperture  204 . 
     With reference now to  FIG. 5 , a high level flow chart of exemplary steps taken by a computer controlled manufacture device (e.g., CCMM  124  shown in  FIG. 1 ) to construct a housing for an electronic device is presented. After initiator block  502 , ferrite mounts are fabricated along one or more edges of an aperture in an enclosure surface of the equipment housing (block  504 ). As described herein, in one embodiment these ferrite mounts are the result of cutting slots near the aperture. As described in block  506 , in order to steer electromagnetically-induced current into the ferrite blocks, impedance holes that extend away from the ferrite mounts (i.e., from the slots that created the ferrite mounts) are cut into the housing. The ferrite blocks are then physically, and thus electrically, connected to the ferrite mounts, such that any electromagnetically-induced current passes through the ferrite blocks for conversion into heat (block  508 ). The process ends at terminator block  510 . 
     The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of various embodiments of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated. 
     Note further that any methods described in the present disclosure may be implemented through the use of a VHDL (VHSIC Hardware Description Language) program and a VHDL chip. VHDL is an exemplary design-entry language for Field Programmable Gate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs), and other similar electronic devices. Thus, any software-implemented method described herein may be emulated by a hardware-based VHDL program, which is then applied to a VHDL chip, such as a FPGA. 
     Having thus described embodiments of the invention of the present application in detail and by reference to illustrative embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims.