Patent Publication Number: US-11652508-B2

Title: Radio frequency waveguide system nodes

Description:
BACKGROUND 
     This disclosure relates to electromagnetic communication, and more particularly to a radio frequency waveguide system with nodes. 
     As control and health monitoring systems become more complex, the interconnect count between system components increases, which also increases failure probabilities. With the increase in interconnects, large amounts of cabling may be used to connect sensors and actuators to controllers and/or diagnostic units of a machine. Long cable runs, including multiple wires, can add substantial weight and may increase susceptibility to noise effects and/or other forms of signal degradation. Increased wire connections can also result in a larger number of wire harnesses to remove and attach when servicing machine components. A larger number of wires and wire harnesses can increase the possibility of damage at pin/socket interconnects, particularly when the wire harnesses are attached and detached from components. 
     To achieve desired control and/or health monitoring, sensing systems may need information from locations that can be difficult to access due to moving parts, internal operating environment or machine configuration. The access limitations can make wire routing bulky, expensive, and potentially vulnerable to interconnect failures. Sensor and interconnect operating environments for desired sensor locations may exceed the capability of interconnect systems. In some cases, cable cost, volume, and weight may exceed desired limits for practical applications. Placement options and total number of sensors and actuators that may be installed in a machine can be limited by wiring and connector impacts on weight, reliability, physical sizing, and operating temperature limitations. 
     BRIEF DESCRIPTION 
     According to one embodiment, a radio frequency waveguide system can include a waveguide interface, a signal splitter, a power rectifier and conditioner, a communication filter, and a network processor. The waveguide interface is configured to communicate through a waveguide in the radio frequency waveguide system. The signal splitter is configured to split a radio frequency transmission received at the waveguide interface between a power path and a communications path within the node. The power rectifier and conditioner are configured to produce a conditioned power signal based on power received through the power path. The communication filter of the communications path is configured to produce a filtered communication signal. The network processor is powered by the conditioned power signal and configured to extract encoded information from the filtered communication signal. 
     In addition to one or more of the features described above or below, or as an alternative, further embodiments may include a control processor configured to interface with a sensor and/or an actuator and to communicate with the network processor, where the control processor is powered by the conditioned power signal. 
     In addition to one or more of the features described above or below, or as an alternative, further embodiments may include a sensor/actuator interface interposed between the control processor and the sensor and/or the actuator, where the sensor/actuator interface is powered by the conditioned power signal and configured to provide power to the sensor and/or the actuator. 
     In addition to one or more of the features described above or below, or as an alternative, further embodiments may include a power filter of the power path. 
     In addition to one or more of the features described above or below, or as an alternative, further embodiments may include where the power rectifier and conditioner includes a power splitter coupled to two or more rectification paths. 
     In addition to one or more of the features described above or below, or as an alternative, further embodiments may include a power threshold trigger configured to selectively output the conditioned power signal based on a power level output exceeding a power threshold. 
     In addition to one or more of the features described above or below, or as an alternative, further embodiments may include where the communication filter is configured to extract the filtered communication signal from a portion of the radio frequency transmission received at the waveguide interface. 
     According to another embodiment, a system for a machine can include a network of a plurality of nodes distributed throughout the machine, each of the nodes associated with at least one sensor and/or actuator of the machine and operable to communicate through one or more radio frequencies. The system can also include a plurality of waveguides configured to guide transmission of the one or more radio frequencies to and from at least one of the nodes, where the at least one of the nodes includes: a waveguide interface configured to communicate through at least one of the waveguides, a signal splitter configured to split a radio frequency transmission received at the waveguide interface between a power path and a communications path within the node, a power rectifier and conditioner configured to produce a conditioned power signal based on power received through the power path, a communication filter of the communications path configured to produce a filtered communication signal, and a network processor powered by the conditioned power signal and configured to extract encoded information from the filtered communication signal. 
     In addition to one or more of the features described above or below, or as an alternative, further embodiments may include where the at least one of the nodes includes a control processor configured to interface with a sensor and/or an actuator of the at least one sensor and/or actuator of the machine and to communicate with the network processor, where the control processor is powered by the conditioned power signal. 
     In addition to one or more of the features described above or below, or as an alternative, further embodiments may include where the at least one of the nodes includes a sensor/actuator interface interposed between the control processor and the sensor and/or the actuator, where the sensor/actuator interface is powered by the conditioned power signal and configured to provide power to the sensor and/or the actuator. 
     In addition to one or more of the features described above or below, or as an alternative, further embodiments may include where the at least one of the nodes includes a power filter of the power path. 
     According to another embodiment, a method can include receiving a radio frequency transmission through a waveguide at a waveguide interface of a node in a radio frequency waveguide system comprising a plurality of nodes. The radio frequency transmission can be split between a power path and a communications path within the node. Power rectification and conditioning can be applied to power received through the power path to produce a conditioned power signal. Power can be provided to a network processor of the node based on the conditioned power signal. A communication filter can be applied to a communications path signal of the communications path to produce a filtered communication signal. The filtered communication signal can be provided to the network processor of the node to extract encoded information. 
     In addition to one or more of the features described above or below, or as an alternative, further embodiments may include interfacing a control processor with the network processor and a sensor and/or an actuator, where the control processor is powered by the conditioned power signal. 
     In addition to one or more of the features described above or below, or as an alternative, further embodiments may include performing power filtering of the power path. 
     In addition to one or more of the features described above or below, or as an alternative, further embodiments may include outputting the conditioned power signal based on a power threshold trigger detecting a power level output exceeding a power threshold. 
     A technical effect of the apparatus, systems and methods is achieved by a radio frequency waveguide system as described herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
         FIG.  1    is a cross-sectional view of a gas turbine engine as an example of a machine; 
         FIG.  2    is a schematic view of a guided electromagnetic transmission network in accordance with an embodiment of the disclosure; 
         FIG.  3    is a schematic view of a configuration including an interface node of a radio frequency waveguide system configured to communicate with end nodes through a wired interface in accordance with an embodiment of the disclosure; 
         FIG.  4    is a schematic view of a configuration including an interface node of a radio frequency waveguide system configured to communicate with an end node through a pin adapter interface in accordance with an embodiment of the disclosure; 
         FIG.  5    is a schematic view of a configuration including an interface node of a radio frequency waveguide system combined with an end node in accordance with an embodiment of the disclosure; 
         FIG.  6    is a schematic view of a portion of a radio frequency waveguide system in accordance with an embodiment of the disclosure; 
         FIG.  7    is a schematic view of a portion of a node of a radio frequency waveguide system in accordance with an embodiment of the disclosure; and 
         FIG.  8    is a flow chart illustrating a method in accordance with an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
     Various embodiments of the present disclosure are related to electromagnetic communication through and to components of a machine.  FIG.  1    schematically illustrates a gas turbine engine  20  as one example of a machine as further described herein. The gas turbine engine  20  is depicted as a two-spool turbofan that generally incorporates a fan section  22 , a compressor section  24 , a combustor section  26  and a turbine section  28 . The fan section  22  drives air along a bypass flow path B in a bypass duct to provide a majority of the thrust, while the compressor section  24  drives air along a core flow path C for compression and communication into the combustor section  26  then expansion through the turbine section  28 . Although depicted as a two-spool turbofan gas turbine engine in the disclosed non-limiting embodiment, it should be understood that the concepts described herein are not limited to use with two-spool turbofans as the teachings may be applied to other types of turbine engines including three-spool architectures or any other machine that requires sensors to operate with similar environmental challenges or constraints. Additionally, the concepts described herein may be applied to any machine or system comprised of control and/or health monitoring systems, for instance, in an aerospace environment. Other examples of machines in which embodiments can be implemented include an internal combustion engine, manufacturing machinery, submarine, aircraft, automobile, or any other machine with control and sensing components. 
     With continued reference to  FIG.  1   , the exemplary engine  20  generally includes a low speed spool  30  and a high speed spool  32  mounted for rotation about an engine central longitudinal axis A relative to an engine static structure  36  via several bearing systems  38 . It should be understood that various bearing systems  38  at various locations may alternatively or additionally be provided, and the location of bearing systems  38  may be varied as appropriate to the application. 
     The low speed spool  30  generally includes an inner shaft  40  that interconnects a fan  42 , a first (or low) pressure compressor  44  and a first (or low) pressure turbine  46 . The inner shaft  40  is connected to the fan  42  through a speed change mechanism, which in exemplary gas turbine engine  20  is illustrated as a geared architecture  48  to drive the fan  42  at a lower speed than the low speed spool  30 . The high speed spool  32  includes an outer shaft  50  that interconnects a second (or high) pressure compressor  52  and a second (or high) pressure turbine  54 . A combustor  56  is arranged in exemplary gas turbine engine  20  between the high pressure compressor  52  and the high pressure turbine  54 . A mid-turbine frame  58  of the engine static structure  36  is arranged generally between the high pressure turbine  54  and the low pressure turbine  46 . The mid-turbine frame  58  further supports bearing systems  38  in the turbine section  28 . The inner shaft  40  and the outer shaft  50  are concentric and rotate via bearing systems  38  about the engine central longitudinal axis A which is collinear with their longitudinal axes. 
     The core airflow is compressed by the low pressure compressor  44  then the high pressure compressor  52 , mixed and burned with fuel in the combustor  56 , then expanded over the high pressure turbine  54  and low pressure turbine  46 . The mid-turbine frame  58  includes airfoils  60  which are in the core airflow path C. The turbines  46 ,  54  rotationally drive the respective low speed spool  30  and high speed spool  32  in response to the expansion. It will be appreciated that each of the positions of the fan section  22 , compressor section  24 , combustor section  26 , turbine section  28 , and fan drive gear system  48  may be varied. For example, gear system  48  may be located aft of combustor section  26  or even aft of turbine section  28 , and fan section  22  may be positioned forward or aft of the location of gear system  48 . In direct drive configurations, the gear system  48  can be omitted. 
     The engine  20  in one example is a high-bypass geared aircraft engine. Low pressure turbine  46  pressure ratio is pressure measured prior to inlet of low pressure turbine  46  as related to the pressure at the outlet of the low pressure turbine  46  prior to an exhaust nozzle. A significant amount of thrust can be provided by the bypass flow B due to the high bypass ratio. The example low pressure turbine  46  can provide the driving power to rotate the fan section  22  and therefore the relationship between the number of turbine rotors  34  in the low pressure turbine  46  and the number of blades in the fan section  22  can establish increased power transfer efficiency. 
     The disclosed example gas turbine engine  20  includes a control and health monitoring system  64  (generally referred to as system  64 ) utilized to monitor component performance and function. The system  64  includes a network  65 , which is an example of a guided electromagnetic transmission network. The network  65  includes a controller  66  operable to communicate with nodes  68   a ,  68   b  through electromagnetic signals. The nodes  68   a ,  68   b  can be distributed throughout the gas turbine engine  20  or other such machine. Node  68   a  is an example of an actuator node that can drive one or more actuators/effectors of the gas turbine engine  20 . Node  68   b  is an example of a sensor node that can interface with one or more sensors of the gas turbine engine  20 . Nodes  68   a ,  68   b  can include processing support circuitry to transmit/receive electromagnetic signals between sensors or actuators and the controller  66 . A coupler  67  can be configured as a splitter between a waveguide  70  coupled to the controller  66  and waveguides  71  and  72  configured to establish wireless communication with nodes  68   a  and  68   b  respectively. The coupler  67  can be a simple splitter or may include a repeater function to condition electromagnetic signals sent between the controller  66  and nodes  68   a ,  68   b . In the example of  FIG.  1   , a radio frequency-based repeater  76  is interposed between the coupler  67  and node  68   b , where waveguide  72  is a first waveguide coupled to the coupler  67  and radio frequency-based repeater  76 , and waveguide  73  is a second waveguide coupled to the radio frequency-based repeater  76  and node  68   b . Collectively, waveguides  70 ,  71 ,  72 ,  73  are configured to guide transmission of the radio frequencies (e.g., electromagnetic signals) between the controller  66  and one or more of the nodes  68   a ,  68   b . The transmission media within waveguides  70 - 73  may include dielectric or gaseous material. In embodiments, the waveguides  70 - 73  can be hollow metal tubes. The waveguides  70 - 73  may be rigid or may include flexible material. The disclosed system  64  may be utilized to control and/or monitor any component function or characteristic of a turbomachine, aircraft component operation, and/or other machines. 
     Prior control &amp; diagnostic system architectures utilized in various applications include a centralized system architecture in which the processing functions reside in an electronic control module. Actuator and sensor communications were accomplished through analog wiring for power, command, position feedback, sensor excitation and sensor signals. Cables and connections include shielding to minimize effects caused by electromagnetic interference (EMI). The use of analog wiring and the required connections can limit application and capability of such systems due to the ability to locate wires, connectors and electronics in harsh environments that experience extremes in temperature, pressure, and/or vibration. Exemplary embodiments can use radio frequencies guided by the waveguides  70 - 73  in a wireless architecture to provide both electromagnetic communication signals and power to the individual elements of the network  65 . 
     The use of electromagnetic radiation in the form of radio waves (MHz to GHz) to communicate and power the sensors and actuators using a traditionally complex wired system provides substantial architectural simplification, especially as it pertains to size, weight, and power (SWaP). Embodiments provide extension of a network where reduced SNR may compromise network performance by trading off data rates for an expansion of the number of nodes and distribution lines; thereby providing more nodes/sensors, with greater interconnectivity. 
     Referring to  FIG.  2   , a guided electromagnetic transmission network  100  is depicted as an example expansion of the network  65  of  FIG.  1   . The guided electromagnetic transmission network  100  can include the controller  66  coupled to coupler  67  through waveguide  170 . The coupler  67  is further coupled to coupler  67   a  through waveguide  171  and to coupler  67   b  through waveguide  172 . Coupler  67   a  is further coupled to three nodes  68   a  through waveguides  173   a ,  173   b ,  173   c  in parallel. Each of the nodes  68   a  can interface or be combined with multiple actuators  102 . Coupler  67   b  is also coupled to two nodes  68   b  through waveguides  174   a ,  174   b  in parallel. Each of the nodes  68   b  can interface or be combined with multiple sensors  104 . Although the example of  FIG.  2    depicts connections to actuators  102  and sensors  104  isolated to different branches, it will be understood that actuators  102  and sensors  104  can be interspersed with each other and need not be isolated on dedicated branches of the guided electromagnetic transmission network  100 . Couplers  67 ,  67   a ,  67   b  can be splitters and/or can incorporate instances of the radio frequency-based repeater  76  of  FIG.  1   . Further, one or more instances of the radio frequency-based repeater  76  can be installed at any of the waveguides  170 ,  171 ,  172 ,  173   a - c , and/or  174   a - b  depending on the signal requirements of the guided electromagnetic transmission network  100 . 
     Nodes  68   a ,  68   b  can be associated with particular engine components, actuators or any other machine part from which information and communication is performed for monitoring and/or control purposes. The nodes  68   a ,  68   b  may contain a single or multiple electronic circuits or sensors configured to communicate over the guided electromagnetic transmission network  100 . 
     The controller  66  can send and receive power and data to and from the nodes  68   a ,  68   b . The controller  66  may be located on equipment near other system components or located remotely as desired to meet application requirements. 
     A transmission path (TP) between the controller  66  and nodes  68   a ,  68   b  can be used to send and receive data routed through the controller  66  from a control module or other components. The TP may utilize waveguides for electromagnetic communication including radio frequency/microwave electromagnetic energy. The interface between the controller  66  and nodes  68   a ,  68   b  can transmit power and communication signals. 
     The example nodes  68   a ,  68   b  may include radio-frequency identification devices along with processing, memory and/or the interfaces to connect to conventional sensors or actuators, such as solenoids or electro-hydraulic servo valves. The waveguides  170 ,  171 ,  172 ,  173   a - c , and/or  174   a - b  can be shielded paths that support electromagnetic communication, including, for instance, radio frequency, microwaves, magnetic or optic waveguide transmission. Shielding can be provided such that electromagnetic energy or light interference  85  with electromagnetic signals  86  (shown schematically as arrows) are mitigated in the guided electromagnetic transmission network  100 . Moreover, the shielding provides that the electromagnetic signals  86  are less likely to propagate into the environment outside the guided electromagnetic transmission network  100  and provide unauthorized access to information. In some embodiments, guided electromagnetic radiation is in the range 1-100 GHz. Electromagnetic radiation can be more tightly arranged around specific carrier frequencies, such as 3-4.5 GHz, 24 GHz, 60 GHz, or 76-77 GHz as examples in the microwave spectrum. One or more carrier frequencies can transmit electric power, as well as communicate information, to multiple nodes  68   a ,  68   b  using various modulation and signaling techniques. 
     The nodes  68   a  with actuators  102  may include control devices, such as a solenoid, switch or other physical actuation devices. Radio frequency identification, electromagnetic or optical devices implemented as the nodes  68   b  with sensors  104  can provide information indicative of a physical parameter, such as pressure, temperature, speed, proximity, vibration, identification, and/or other parameters used for identifying, monitoring or controlling component operation. Signals communicated in the guided electromagnetic transmission network  100  may employ techniques such as checksums, hash algorithms, error control algorithms and/or encryption to mitigate cyber security threats and interference. 
     The guided electromagnetic transmission network  100  may be installed in a mixed temperature environment, such as a machine having a hotter portion and a cooler portion. In reference to the example of  FIG.  1   , the fan section  22  and compressor section  24  of the gas turbine engine  20  can be designated as cooler portions relative to hotter portions of the gas turbine engine  20 , such as the combustor section  26  and turbine section  28 . To further accommodate the temperature variations within the gas turbine engine  20 , a variety of approaches can be used. As one example, electronics devices within the nodes  68   a ,  68   b , actuators  102 , and/or sensors  104  can include wide band gap semiconductor devices, such as silicon carbide or gallium nitride devices supporting higher operating temperatures than typical semiconductor devices. Placement of the nodes  68   a ,  68   b  can also impact performance capabilities in the hotter portion of the machine. Where actuators  102  or sensors  104  are needed at locations that would potentially exceed the desired operating temperature of the nodes  68   a ,  68   b  that directly interface with the actuators  102  or sensors  104 , relatively short wired connections, referred to as “pigtails” can be used between the nodes  68   a ,  68   b  and the actuators  102  or sensors  104 . The pigtail wiring can provide thermal separation and may support the use of legacy wired actuators  102  and sensors  104  to connect with nodes  68   a ,  68   b . Further temperature accommodations may include cooling systems, heat sinks, and the like. 
     In some embodiments, shielding in the guided electromagnetic transmission network  100  can be provided such that power and communication signals are shielded from outside interference, which may be caused by environmental electromagnetic or optic interference. Moreover, the shielding limits intentional interference  85  with communication at each component. Intentional interference  85  may take the form of unauthorized data capture, data insertion, general disruption and/or any other action that degrades system communication. Environmental sources of interference  85  may originate from noise generated from proximate electrical systems in other components or machinery along with electrostatic and magnetic fields, and/or any broadcast signals from transmitters or receivers. Additionally, environmental phenomena, such as cosmic radio frequency radiation, lightning or other atmospheric effects, could interfere with local electromagnetic communications. 
     It should be appreciated that while the system  64  is explained by way of example with regard to a gas turbine engine  20 , other machines and machine designs can be modified to incorporate built-in shielding for monitored or controlled components in a guided electromagnetic transmission network. For example, the system  64  can be incorporated in a variety of harsh environment machines, such as manufacturing and processing equipment, a vehicle system, an environmental control system, and all the like. As a further example, the system  64  can be incorporated in an aerospace system, such as an aircraft, rotorcraft, spacecraft, satellite, or the like. The disclosed system  64  includes the network  65 ,  100  that provides consistent communication with electromagnetic devices, such as the example nodes  68   a ,  68   b , and removes variables encountered with electromagnetic communications such as distance between transmitters and receiving devices, physical geometry in the field of transmission, control over transmission media such as air or fluids, control over air or fluid contamination through the use of filtering or isolation and knowledge of temperature and pressure. 
     The system  64  provides for a reduction in cable and interconnecting systems to reduce cost and increases reliability by reducing the number of physical interconnections. Reductions in cable and connecting systems further provides for a reduction in weight while enabling additional redundancy. Moreover, additional sensors can be added without the need for additional wiring and physical connections to the controller  66 , which may provide for increased system accuracy and response. Embodiments can provide a “plug-n-play” approach to add a new node, potentially without a requalification of the entire system but only the new component; thereby greatly reducing qualification burdens. 
       FIG.  3    is a schematic view of a configuration  200  including an interface node  68  of a radio frequency waveguide system, such as system  64  of  FIG.  1   , configured to communicate with end nodes  202  through a wired interface  204 . The interface node  68  can be a generalized example of nodes  68   a ,  68   b  of  FIGS.  1  and  2   , where the end nodes  202  may include one or more actuators  102 , one or more sensors  104 , or a combination thereof. The interface node  68  can also be generally referred to as a node  68 . The wired interface  204  may be a pigtail connection allowing for a relatively short length of wire to connect the interface node  68  with the end nodes  202 . For instance, the length of the wired interface  204  may enable the interface node  68  to be placed in a relatively cooler portion of a machine than where the end nodes  202  are located, such as in a bypass duct or proximate to a cooling side of a heat exchanger. The wired interface  204  enables the interface node  68  to electrically interface with the end nodes  202  while supporting radio frequency communication  206  with other system components through one or more waveguides  208 ,  210 ,  212 , couplers  67 , and other such system elements as previously described with respect to  FIGS.  1  and  2   . 
       FIG.  4    is a schematic view of a configuration  300  including an interface node  68  of a radio frequency waveguide system, such as system  64  of  FIG.  1   , configured to communication with an end node  202  through a pin adapter interface  302 . The interface node  68  can be a generalized example of nodes  68   a ,  68   b  of  FIGS.  1  and  2   , where the end node  202  may be an actuator  102  or sensor  104 . The pin adapter interface  302  can enable a direct connection between the interface node  68  and the end node  202  without a larger physical separation of the wired interface  204  of  FIG.  3   . The pin adapter interface  302  may have a socket connection to support in-field replacement of the end node  202  without replacing the interface node  68 . Alternatively, the pin adapter interface  302  may be more securely coupled, for instance, by soldering or otherwise coupling pins of the end node  202  to the interface node  68 . The pin adapter interface  302  enables the interface node  68  to electrically interface with the end nodes  202  while supporting radio frequency communication  206  with other system components through one or more waveguides  208 ,  210 ,  212 , couplers  67 , and other such system elements as previously described with respect to  FIGS.  1  and  2   . The pin adapter interface  302  may be a lighter weight than the wired interface  204  of  FIG.  3   . In contrast, the interface node  68  in configuration  300  may be placed in closer proximity to a same temperature environment of end node  202  than in configuration  200  of  FIG.  3   . 
       FIG.  5    is a schematic view of a configuration  400  including an interface node  68  of a radio frequency waveguide system, such as system  64  of  FIG.  1   , disposed in a shared housing  402  with an end node  202 . The interface node  68  can be a generalized example of nodes  68   a ,  68   b  of  FIGS.  1  and  2   , where the end node  202  may include one or more actuators  102 , one or more sensors  104 , or a combination thereof within the shared housing  402 . The shared housing  402  combines the interface node  68  and end node  202  as a line replaceable unit. The interface node  68  and end node  202  may be electrically coupled within the shared housing  402 , while the interface node  68  supports radio frequency communication  206  with other system components through one or more waveguides  208 ,  210 ,  212 , couplers  67 , and other such system elements as previously described with respect to  FIGS.  1  and  2   . 
       FIG.  6    is a schematic view of a portion of a radio frequency waveguide system  500  illustrating further details of controller  66 , interface node  68 , and end nodes  202 . In the example of  FIG.  6   , the controller  66  is depicted as a dual channel controller, where a first channel  502  and a second channel  504  can each include a communication interface  506 , a processing system  508 , and a memory system  510 . The communication interface  506  can use a software defined radio or other protocol to support communication using electromagnetic signals. The processing system  508  can include any type or combination of central processing unit (CPU), including one or more of: a microprocessor, a digital signal processor (DSP), a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or the like supported in the expected operating environment. The memory system  510  may include random access memory (RAM), read only memory (ROM), or other electronic, optical, magnetic, or any other computer readable medium onto which data and algorithms are stored in a non-transitory form. 
     A radio frequency communication link  512  between the controller  66  and interface node  68  can be shared by both the first channel  502  and second channel  504 , or each channel  502 ,  504  may have independent radio frequency communication links  512  to one or more instances of the interface node  68 . The controller  66  may also provide a power link  514  to the interface node  68 . The radio frequency communication link  512  and power link  514  can be transmitted through radio frequencies within a same waveguide  516 . 
     The interface node  68  can include a waveguide interface  519  configured to receive a radio frequency transmission through waveguide  516  in the radio frequency waveguide system  500 . The waveguide interface  519  can include one or more radio frequency antennas  520  to receive and/or send transmissions between the interface node  68  and the controller  66  and/or other nodes. The waveguide interface  519  need not include the one or more radio frequency antennas  520  but may instead use a rectenna, a transformer, a waveguide adaptor, or other such structure to support signal/power transmission and reception through the waveguide  516 . The interface node  68  can also include a signal splitter  522  configured to split the radio frequency transmission between a power path  524  and a communications path  526  within the node  68 . A power filter  528  of the power path  524  is configured to produce a filtered power signal  530 . A power rectifier  532  and conditioner  534  (also referred to as power conditioning circuit  534 ) are configured to produce a conditioned power signal  536 . A communication filter  538  of the communications path  526  can be configured to produce a filtered communication signal  540 . The power filter  528  and/or the communication filter  538  can be implemented using various filter components and structures. For example, the power filter  528  and/or the communication filter  538  can be implemented using bulk acoustic wave filters, feedthrough filters, waveguide filters, metallization-based filters, and other such structures. As such, a portion of the filtering may be performed external to the interface node  68 , such as, within the waveguide  516  coupled to the waveguide interface  519 . 
     The interface node  68  can also include a network processor  542  powered by the conditioned power signal  536  and configured to extract encoded information from the filtered communication signal  540 . A control processor  544  can be configured to interface with one or more sensors  104  and/or actuators  102  and to communicate with the network processor  542 . The control processor  544  can be powered by the conditioned power signal  536 . A sensor/actuator interface  546  can be interposed between the control processor  544  and the sensors  104  and/or the actuators  102 . The sensor/actuator interface  546  can be powered by the conditioned power signal  536  and configured to provide power to the sensors  104  and/or the actuators  102 , for instance, through electrical interfacing  554 ,  552  respectively. The electrical interfacing  554 ,  552  can include use of the wired interface  204  of  FIG.  3   , the pin adapter interface  302  of  FIG.  4   , and/or a direct connection within the shared housing  402  of  FIG.  5   . In some embodiments, the conditioned power signal  536  may receive power from an alternate or supplemental source  550 . For example, a battery backup or external power supply can be used as the alternate or supplemental source  550  to supplement power transmissions through the radio frequency waveguide system  500 . 
     Electrical components within the interface node  68  can be made of high-temperature capable materials using, for example passive elements and/or semiconductor diodes to survive high temperatures, such as an engine core. For instance, components can be made of one or more wide band gap semiconductors. Materials for high-temperature application can include silicon carbide, gallium nitride, aluminum nitride, aluminum scrandium nitride, and other such materials. This can enable the interface node  68  to be placed in a hotter portion of a machine, such as the gas turbine engine  20 , while the controller  66  may be at a cooler location, such as on a fan case of the fan section  22 . 
     Processing performed by the control processor  544  can include signal filtering, engineering unit conversion, fault detection, fault isolation, and built-in test, for example. The network processor  542  can perform communication management for receiving and sending data on the radio frequency communication link  512 . Depending on the processing capacity of the control processor  544  and network processor  542 , more advanced sensing and detection algorithms can be locally incorporated to offload some processing burdens of the controller  66 . Lower-level signal conditioning can be handled by the sensor/actuator interface  546 , such as analog filtering, sampling, conversions, excitation signal generation, and other such functions. Although depicted separately, the network processor  542 , the control processor  544 , and/or the sensor/actuator interface  546  can be combined or further subdivided. 
       FIG.  7    depicts an example of a portion of the interface node  68  of the radio frequency waveguide system  500  of  FIG.  6    in greater detail. An antenna feed  602  can link the waveguide interface  519  of  FIG.  6   , such as one or more radio frequency antennas  520  of  FIG.  6   , to the signal splitter  522  that performs power and signal splitting with respect to the power path  524  and the communications path  526 . The power filter  528  can be implemented, for example, as a bandpass filter formed as a first metallization pattern on a circuit board  600  of the interface node  68  in the example of  FIG.  7   . Alternatively, the power filter  528  may be omitted or implemented using other filter structures/components, such as a combination of high pass and low pass filters or a combination of stopband filters. The power filter  528  can be omitted, for instance, where the signal and power splitter  522  is implemented as a diplexer that incorporates splitting and filtering components. The power rectifier  532  and conditioner  534  can be implemented, for example, as a power splitter  606  coupled to two or more rectification paths  608 , and each of the rectification paths  608  can be coupled to a power conditioning circuit  534 . The power splitter  606  can receive the filtered power signal  530  from the power filter  528 . The two or more rectification paths  608  can include a second metallization pattern on the circuit board  600  of the interface node  68  or be implemented using other filter structures/components. For instance, the use of metallization patterns in the two or more rectification paths  608  can incorporate rectification filters. The power conditioning circuitry  534  can include a power threshold trigger  612  configured to selectively output the conditioned power signal  536  of  FIG.  6    based on a power level output exceeding a power threshold. The power threshold trigger  612  can help to ensure that components of the interface node  68  are not partially powered which could result in an indeterminate or error state of operation. Further, the communication filter  538  can be configured to extract the filtered communication signal  540  of  FIG.  6    from a portion of the radio frequency transmission received at the radio frequency antenna  520 . Where the signal and power splitter  522  is implemented as a diplexer that incorporates splitting and filtering components, the communication filter  538  may be omitted or modified. A board-to-board jumper  616  can be used to connect the output of the communication filter  538  to another printed circuit board that may include devices and interfaces, such as the network processor  542 , control processor  544 , and sensor/actuator interface  546  of  FIG.  6   . The combined printed circuit boards may have a compact footprint, such as about 1.2 inches by 1.2 inches (i.e., about 3 cm by 3 cm). Although the example of  FIG.  7    depicts two rectification paths  608 , embodiments can include any number of rectification paths as needed depending on power level requirements and other such constraints. 
       FIG.  8    is a flow chart illustrating a method  700  of establishing electromagnetic communication through one or more nodes in a machine, such as the gas turbine engine  20  of  FIG.  1    in accordance with an embodiment. The method  700  of  FIG.  8    is described in reference to  FIGS.  1 - 7    and may be performed with an alternate order and include additional steps. Further steps can be performed in parallel and are not necessarily sequential actions. For purposes of explanation, the method  700  is primarily described in reference to  FIG.  6    but can also be implemented on the system  64  of  FIG.  1   , the guided electromagnetic transmission network  100  of  FIG.  2   , and other network variations and a variety of machines. The machine may operate in or produce a mixed temperature environment including higher temperatures (e.g., &gt;150 degrees C.) beyond the normal range of microelectronics, which is typically less than 100 degrees C. The local temperature at different sections of the machine can vary substantially, such as upstream from combustion, at a fuel combustion location, and downstream from combustion. 
     At block  702 , a radio frequency transmission is received through a waveguide  516  at a waveguide interface  519 , such as at one or more radio frequency antennas  520  of a node  68  in a radio frequency waveguide system  500  that can include a plurality of nodes. Examples can include nodes  68 ,  68   a ,  68   b , and the machine can be the gas turbine engine  20  of  FIG.  1   . 
     At block  704 , the radio frequency transmission is split between a power path  524  and a communications path  526  within the node  68 . 
     At block  706 , a power filter  528  can be applied to a power path signal of the power path  524  to produce a filtered power signal  530 . Alternatively, power filtering can be performed integrally with other components. 
     At block  708 , power rectification and conditioning can be applied by power rectifier  532  and conditioner  534  to produce a conditioned power signal  536  based on power received through the power path  524 . For instance, the filtered power signal  530  can be rectified and further conditioned using one or more bandpass filters. 
     At block  710 , power can be provided to a network processor  542  of the node  68  based on the conditioned power signal  536 . 
     At block  712 , a communication filter  538  can be applied to a communications path signal of the communications path  526  to produce a filtered communication signal  540 . 
     At block  714 , the filtered communication signal  540  can be provided to the network processor  542  of the node  68  to extract encoded information. A control processor  544  can be interfaced with the network processor  542  and a sensor  104  and/or an actuator  102 . The control processor  544  can be powered by the conditioned power signal  536 . 
     In embodiments, the nodes  68 ,  68   a ,  68   b  can be portions of a network  65  configured to communicate through a plurality of electromagnetic signals, where the nodes  68 ,  68   a ,  68   b  are distributed throughout the machine, such as the gas turbine engine  20 . Multiple nodes  68 ,  68   a ,  68   b  can be used in a complete system  64  to take advantage of architecture scalability. Each of the nodes  68 ,  68   a ,  68   b  can be associated with at least one actuator  102  or sensor  104  of the gas turbine engine  20 . For example, one or more of the nodes  68 ,  68   a ,  68   b  can be located at one or more of a fan section  22 , a compressor section  24 , a combustor section  26 , and/or a turbine section  28  of the gas turbine engine  20 . 
     A variety of node configurations can be supported, and the node configurations can be mixed within the network. For example, at least one of the nodes  68   a ,  68   b  can be an interface node  68  that communicates with one or more end nodes  202 . One or more end nodes  202  can be coupled to the interface node  68  through a wired interface  204 . As further example, the one or more end nodes  202  can be coupled to the interface node  68  through a pin adapter interface  302 . As another example, the one or more end nodes  202  can be coupled to the interface node  68  and disposed in a shared housing  402 . 
     The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, “about” can include a range of ±8% or 5%, or 2% of a given value. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. 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, element components, and/or groups thereof. 
     While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.