Patent Publication Number: US-11378605-B2

Title: Method for high-intensity radiated field (HIRF) and electromagnetic pulse (EMP) analysis of a vehicle

Description:
BACKGROUND 
     1. Technical Field 
     The field of the invention relates generally to systems and methods of analyzing and testing the electrical properties of a vehicle, and more specifically, to methods and systems for analyzing and testing the high-intensity radiated field (HIRF) and/or electromagnetic pulse (EMP) characteristics of the vehicle. 
     2. Prior Art 
     At present, determining the HIRF and/or EMP characteristics of a vehicle, such as an aircraft, is very important. For example, HIRF and/or EMP analysis and testing is an essential part of aircraft development and certification. The reason for this is that aircraft and other types of vehicles (such as, for example, military types of ships or ground vehicles) have increased their use of mission critical equipment, new composite materials that have reduced electromagnetic shielding, electrical and electronic systems configured to perform more flight and landing functions, and new devices and systems that are susceptible to HIRF due to increased data bus and processor operating speeds, higher density integrated circuits and cards, and greater general sensitivities of the electronic equipment. 
     Generally, determining the HIRF and/or EMP characteristics of these types of vehicles involves placing the vehicle within an outdoor range where the vehicle is surrounded by radiating sensors that emit plane wave signals that are radiated at the vehicle, scattered by the vehicle, and correspondingly detected by the radiating sensors. This process is repeated for different angles of incidence towards the vehicle. The detected signals are then utilized to analyze the HIRF and/or EMP characteristics of the vehicle. Unfortunately, this type of outdoor field testing is expensive and time-consuming. 
     Approaches to address these problems have included attempting to replace the expensive and time-consuming outdoor field testing with a computer modeling approach. Unfortunately, due to the ever-increasing complexity of electrical systems in modern vehicles, such as aircraft, efficient aircraft-scale HIRF and/or EMP analysis is computationally prohibitive because an aircraft-scale plane wave incidence electromagnetic (EM) simulation run with a specific signal waveform and propagation direction and/or polarization may take days in a multi-node cluster process and produce tens of gigabytes of data. Moreover, for each different signal waveform and propagation direction and/or polarization, an expensive EM simulation must be launched and run, and the resulting huge amount of data must be saved in storage. Furthermore, as the electrification of aircraft continues to make rapid progress and more sophisticated electronics are integrated on-board, the computational complexity of modeling “victim” components (e.g., cables, connectors, system board, etc.) for HIRF and/or EMP analysis is ever more challenging. As such, there is a need for a system and method to address these issues. 
     SUMMARY 
     A method for modeling electromagnetic characteristics of a vehicle having electrical components is disclosed. The method comprises generating a parallel plate waveguide model having a first waveguide port and a second waveguide port and inserting a vehicle model for the vehicle within the parallel plate waveguide model. The vehicle model has a plurality of lumped ports corresponding to the electrical components on-board the vehicle. The method further comprises executing an electromagnetic field solver on the first waveguide port, the second waveguide port, and the plurality of lumped ports and determining a scaling factor between a first power level configured to excite the first waveguide port and/or the second waveguide port and a second power level configured to excite the plurality of lumped ports. The electromagnetic field solver is executed on the first waveguide port, the second waveguide port, and the plurality of lumped ports, and the electromagnetic field solver produces a first output data. The method further comprises producing a scattering parameter (S-parameter) model for the vehicle from the first output data, where the S-parameter model includes a plurality of S-parameter ports, generating a plurality of excitation signals at the plurality of S-parameter ports, where the scaling factor has been applied to the plurality of excitation signals, and executing a time-domain circuit simulation to model the electromagnetic characteristics of the vehicle. 
     Other devices, apparatuses, systems, methods, features, and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional devices, apparatuses, systems, methods, features, and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The invention may be better understood by referring to the following figures. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views. 
         FIG. 1  is a system diagram of a conventional outdoor range. 
         FIG. 2  is a system diagram of an operation of the outdoor range shown in  FIG. 1 . 
         FIG. 3  is a system diagram of an example of an implementation of a system for modeling the electromagnetic characteristics of a vehicle in accordance with the present disclosure. 
         FIG. 4  is a flowchart of an example of an implementation of a method performed by the system shown in  FIG. 3  in accordance with the present disclosure. 
         FIG. 5  is a system diagram of an example of an implementation of a plane wave port set-up of a parallel plate waveguide model for use by the system and method shown in  FIGS. 3 and 4  in accordance with the present disclosure. 
         FIG. 6  is a system diagram of an example of an implementation of an equivalent S-parameter network of the plane wave port set-up of the parallel plate waveguide model shown in  FIG. 5  in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Disclosed is a method for modeling electromagnetic characteristics of a vehicle having electrical components. The method comprises generating a parallel plate waveguide model having a first waveguide port and a second waveguide port and inserting a vehicle model for the vehicle within the parallel plate waveguide model. The vehicle model has a plurality of lumped ports corresponding to the electrical components on-board the vehicle. The method further comprises executing an electromagnetic field solver on the first waveguide port, the second waveguide port, and the plurality of lumped ports and determining a scaling factor between a first power level configured to excite the first waveguide port and/or the second waveguide port and a second power level configured to excite the plurality of lumped ports. The electromagnetic field solver is executed on the first waveguide port, the second waveguide port, and the plurality of lumped ports, and the electromagnetic field solver produces a first output data. The method further comprises producing a scattering parameter (S-parameter) model for the vehicle from the first output data, where the S-parameter model includes a plurality of S-parameter ports, generating a plurality of excitation signals at the plurality of S-parameter ports, where the scaling factor has been applied to the plurality of excitation signals, and executing a time-domain circuit simulation to model the electromagnetic characteristics of the vehicle. 
     In  FIG. 1 , a system diagram of a conventional outdoor range  100  is shown. In this example, the outdoor range  100  includes a plurality of radiating sensors  102 ,  104 ,  106 ,  108 ,  110 ,  112 ,  114 ,  116 ,  118 , and  120  arranged in an approximate circle along the ground  122 . A vehicle  124  (in this example an aircraft) is placed on the ground  122  within the area of the approximate circle defined by the radiating sensors  102 ,  104 ,  106 ,  108 ,  110 ,  112 ,  114 ,  116 ,  118 , and  120 . In this example, the radiating sensors  102 ,  104 ,  106 ,  108 ,  110 ,  112 ,  114 ,  116 ,  118 , and  120  may be antenna elements capable of both transmitting and receiving signals and the vehicle  124  may be oriented along a main axis  126  that extends between the radiating sensors  102  and  112 . The other radiating sensors  104 ,  106 ,  108 ,  110 ,  114 ,  116 ,  118 , and  120  may extend along minor axes  128 ,  130 ,  132 , and  134 . In this example, the number of radiating sensors  102 ,  104 ,  106 ,  108 ,  110 ,  112 ,  114 ,  116 ,  118 , and  120  may vary based on the design of the outdoor range  100 . 
     In addition to the plurality of radiating sensors  102 ,  104 ,  106 ,  108 ,  110 ,  112 ,  114 ,  116 ,  118 , and  120 , the vehicle  124  may also include a plurality of vehicle sensors  136 ,  138 ,  140 ,  142 ,  144 ,  146 ,  148 ,  150 , and  152  located on the surface  154  of the vehicle  124  and within the vehicle  124 . In this example, the vehicle sensors within the vehicle  124  are not shown but are located within the vehicle  124  for HIRF/EMP field tests. 
     In  FIG. 2 , a system diagram of an operation of the outdoor range  100  is shown. In this example, a boresight first plane wave  200  is shown being radiated from the first radiating sensor  102  to the front of the vehicle  124  along the main axis  126  in a first direction  202  towards the second radiating sensor  112 . Likewise, a second plane wave  204  is shown being radiated from the second radiating sensor  112  to the back of the vehicle  124  along the main axis in a second direction  206  towards the first radiating sensor  102 . 
     The resulting scattering of the first plane wave  200 , or second plane wave  204 , caused by the vehicle  124  is detected by the other radiating sensors  104 ,  106 ,  108 ,  110 ,  114 ,  116 ,  118 , and  120  and utilized to produce the HIRF and/or EMP characteristics of the vehicle for a given angle of incidence towards the vehicle  124 . This process is then repeated for different angles of incidence around the vehicle  124 . Unfortunately, this type of outdoor field testing is expensive and time-consuming. 
     In  FIG. 3 , a system diagram of an example of an implementation of a system  300  for modeling electromagnetic characteristics of a vehicle  124  is shown in accordance with the present disclosure. In this example, the system  300  may include a computing device  302  and a storage  304 . The storage  304  may be, for example, a hard drive, a memory module (e.g., random access memory (RAM) and/or read-only memory (ROM)), flash drive, or other type of storage device. The computing device  302  may include one or more processors  306  (also known as processing units), a memory  308 , and one or more communication interfaces  310 . The memory  308  may include a computer-readable medium  312  (also known as a computer-readable media, machine-readable medium, or machine-readable media) and software  314 . In this example, the computer-readable medium  312  stores executable instructions that, when executed by the one or more processors  306 , cause the system  300  to perform the method described in  FIG. 4 . In this example, the computing device  302  may receive a vehicle model  316  from an external source such as, for example, the storage  304  or another external device. Alternatively, the vehicle model  316  may be generated by the computing device  302  from measured test data of the vehicle  124  previously taken at an outdoor range. In general, the vehicle model  316  is a computer-generated model of the vehicle  124  that includes the electrical characteristics of the vehicle  124 . 
     In this example, the computing device  302  may belong to a variety of classes of devices, such as traditional client-type devices, desktop computer-type devices, server computer-type devices, or special purpose-type devices. Thus, the computing device  302  may be (but is not limited to) a desktop computer, a work station, a server, a distributed computing system, or any other sort of computing device having sufficient computational power to run the method for modeling the electromagnetic characteristics of the vehicle  124 . 
     The one or more communication interfaces  310  may include input/output (“I/O”) interfaces (not shown) that enable communications with input/output devices  318  such as, for example, user input devices that include peripheral input devices (e.g., a keyboard, a mouse, a pen, a voice input device, a touch input device, a gestural input device, and the like) and/or output devices that include peripheral output devices (e.g., a display, a printer, audio speakers, and the like). The one or more communication interfaces  310  may also enable communications between the computing device  302  and other networked devices, such as other remote computing devices (not shown), servers (not shown) and/or other external devices over the one or more network(s)  320 . In this example, the one or more communication interfaces  310  may include one or more network interface controllers (NICs) or other types of transceiver devices to send and receive communications and/or data over the one or more network(s)  320 . As an example, the computing power of the computing device  302  may be increased by distributing computations with other computing devices that are connected to the computing device  302  via the one or more network(s)  320 . 
     The one or more processors  306  may be operably connected to the computer-readable medium  312  via a bus, which may include one or more system buses, a data bus, an address bus, a PCI bus, a Mini-PCI bus, and any variety of local, peripheral, and/or independent buses. The executable instructions stored on the computer-readable medium  312  may include, for example, an operating system, a client module, a profile module, and other software modules, programs, or applications that are loadable and executable by the one or more processors  306 . 
     In  FIG. 4 , a flowchart of an example of an implementation of a method  400  performed by the system  300  is shown in accordance with the present disclosure. Generally, the method  400  includes first generating  402  an S-parameter model for the vehicle  124 , determining  404  a scaling power factor (e.g. from a waveguide port power compared to the lumped port power), and executing  406  a simulation utilizing the S-parameter model  406 . 
     Specifically, the method  400  starts and generates  408  a parallel plate waveguide model having a first waveguide port and a second waveguide port and inserts  410  the vehicle model  316  for the vehicle  124  within the parallel plate waveguide model, where the vehicle model  316  has a plurality of lumped ports corresponding to the electrical components of the vehicle  124 . The method  400  may also include an optional step of generating  412  the vehicle model  316  (e.g. an aircraft model) with the computing device  302 . The method  400  then executes  414  an electromagnetic field (e.g. EM) solver on the first waveguide port, the second waveguide port, and the plurality of lumped ports, where the electromagnetic field solver produces a first output data including scattering parameter (S-parameter) data. In general, as appreciated by those of ordinary skill of the art, an EM solver (also known as a “field solver”) is a specialized program that solves (a subset of) Maxwell&#39;s equations directly. The method  400  further determines  404  a scaling factor between a first power level configured to excite the first waveguide port and the second waveguide port, and a second power level configured to excite the plurality of lumped ports and produces  416  a S-parameter model for the vehicle model  316  from the first output data, where the S-parameter model includes a plurality of S-parameter ports. The method  400  then saves  418  the S-parameter model in the storage  304  such as a computer memory. In this example, the stored S-parameter model is reusable for executing a system level transient simulation utilizing the S-parameter model at a later time. As an example, the S-parameter model may be saved in storage  304  as a Touchstone or SnP file. 
     The method  400  then executes  406  the simulation utilizing the S-parameter model by retrieving  420  the S-parameter model for modeling the electrical system under plane wave illumination and generating  422  a plurality of excitation signals at the plurality of S-parameter ports, where the scaling power factor (from step  404 ) has been applied to the plurality of excitation signals. The method  400  then executes  424  a time-domain circuit simulation to model the electromagnetic characteristics of the vehicle model  316  and the method  400  ends. 
     In this example, the vehicle model  316  may be predetermined in that it is an electrical representation of the vehicle  124  that has been created prior to its use in the present method  400 . However, the system  300  may be part of a larger system (not shown) that includes an outdoor range and is capable of testing the vehicle  124  to produce the vehicle model  316  (as recited in step  412  above) with the computing device  302 . 
     In this disclosure, each lumped port of the plurality of lumped ports is configured to have electrical properties corresponding to an on-board component, device, module, or system of the vehicle  124  and the first waveguide port and the second waveguide port are configured to simulate a plane wave illumination of the vehicle  124 . As an example, if the vehicle model  316  is an aircraft, the lumped ports may represent an avionic on-board component, device, module, or system terminals inside the aircraft that are usually connected to each other by cables that may be part of a cable harness (also known as a wire harness). 
     When determining  404  the scaling factor, the first power level is higher than the second power level because the first power level is a simulated power level of the first plane wave  200  and/or second plane wave  204  that are directed at the entire outside surface of the vehicle model  316 . In this example, the first power level is determined based a cross-section of a waveguide defined by the parallel plate waveguide model and an incident plane wave generated by the electromagnetic field solver at the first waveguide port or the second waveguide port. The second power level is lower than the first power level because the second power level represents a power level that is sufficient to power the individual lumped ports of the plurality of lumped ports that correspond to the on-board components, devices, modules, or systems of the vehicle model  316 . Based on the design tool utilized, the second power level may vary. As an example, if a CST Suite T-solver (produced by Dassault Systèmes of Vélizy-Villacoublay, France) is utilized, the second power level may be, for example, approximately 0.5 Watts (rms). 
     Turning to  FIG. 5 , a system diagram of an example of an implementation of a plane wave port set-up of a parallel plate waveguide model  500  for use by the system  300  and method  400  is shown in accordance with the present disclosure. In this example, the parallel plate waveguide model  500  is shown as a three-dimensional (3D) computational model generated  408  by the system  300 . The parallel plate waveguide model  500  includes a top conductive plate  502  and a bottom conductive plate  504  having a first waveguide port  506  and a second waveguide port  508  at opposite sides of the parallel plate waveguide model  500 . The first waveguide port  506  has a first electric field (E-Field)  510  and a first magnetic field (H-Field)  512  and the second waveguide port  508  has a second E-Field  514  and a second H-Field  516 . The vehicle model  316  is inserted  410  into the parallel plate waveguide model  500 . The vehicle model  316  has electrical ports and connecting cables inside which will be influenced by electromagnetic waves that penetrate inside the vehicle model  316 . 
     In this example, a plane wave illumination for a high-intensity radiated field (HIRF) and/or an electromagnetic pulse (EMP) is conducted inside the parallel plate waveguide model  500 , where a pair of plane waves (i.e., a first plane wave  518  and a second plane wave  520 ) are incident on the inserted vehicle model  316 . The first plane wave  518  and second plane wave  520  travel in opposite directions and with opposite field polarizations towards the vehicle model  316 . 
     In this example, the vehicle model  316  is shown as located at approximately the center position within the parallel plate waveguide model  500  facing the first waveguide port  506 . The vehicle model  316  is shown as comprising a plurality of lumped ports. For the purposes of illustration, six lumped ports  522 ,  524 ,  526 ,  528 ,  530 , and  532  are shown along a surface  534  of the vehicle model  316 . It is appreciated by those of ordinary skill in the art that the six (6) lumped ports  522 ,  524 ,  526 ,  528 ,  530 , and  532  are not a limitation on the number of lumped ports that may be utilized with the vehicle model  316  and any number of lumped ports may be utilized instead of just six (6) lumped ports without departing from the scope of the present disclosure. Moreover, the vehicle model  316  may also include lumped ports (not shown) that are inside the vehicle model  316 . 
     The vehicle model  316  is also shown, as an example, to include a plurality of cable connections that may be part of a cable harness for electrically connecting multiple lumped ports that represent component terminals inside the vehicle model  316 . For example, the first lumped port  522  is shown electrically connected to the second lumped port  524  with a first cable connection  536  and to the third lumped port  526  with a second cable connection  538 . The second lumped port  524  is also shown electrically connected to the fourth lumped port  528  with a third cable connection  540  and the fifth lumped port  530  is shown electrically connected to the sixth lumped port  532  with a fourth cable connection  542 . In this example, the first cable  536 , the second cable  538 , the third cable  540 , and the fourth cable  542  are located within the vehicle model  316 . 
     In an example of operation, the computing device  302  sets up the parallel plate waveguide model  500  in a 3D electromagnetic field solver and places the vehicle model  316  within the parallel plate waveguide model  500 . As discussed earlier, the vehicle model  316  includes the electrical ports (i.e., lumped ports  522 ,  524 ,  526 ,  528 ,  530 , and  532 ) and the connecting cables (i.e., cables  536 ,  538 ,  540 , and  542 ) that are inside the vehicle model  316  and which will be influenced by the electromagnetic waves penetrating inside the vehicle model  316 . The computing device  302  then executes the 3D electromagnetic field solver where each port is individually excited while the other ports passively receive electromagnetic waves (i.e., energy) from the excited port. Again, in this example, the lumped ports represent the electrical terminals onboard the vehicle model  316  and the wave ports (i.e., the first waveguide port  506  and the second waveguide port  508  of the parallel plate waveguide model  500 ) represent the plane wave illumination of the vehicle model  316 . As a result, this process will extract the S-parameter model (i.e., the S-parameter matrix) for the vehicle model  316 . The computing device  302  then calculates the S-parameter model from the output data produced by the 3D electromagnetic field solver where the output data is E-field and H-field data. The S-parameter model is formatted in an industry standard data file format (e.g., a Touchstone file) that may be a compact ASCII text file and then is saved in the storage  304 . 
     In this example, when the 3D electromagnetic field solver is finished running, the computing device  302  may calculate the scaling factor from the waveguide port power (at the first waveguide port  506  or the second waveguide port  508 ) compared to the lumped port power (at the lumped ports  522 ,  524 ,  526 ,  528 ,  530 , and  532 ). Generally, the lumped ports (i.e., lumped ports  522 ,  524 ,  526 ,  528 ,  530 , and  532 ) correspond to the electrical terminals that push a relatively low amount of power into the system while the first waveguide port  506  and/or the second waveguide port  508  correspond to radiated plane waves that have power levels injected into the parallel plate waveguide model  500  that depend upon the size of the waveguide cross section of the parallel plate waveguide model  500  and the power density of the incident plane wave (i.e., the first plane wave  518  and/or the second plane wave  520 ). This difference in power level among the waveguide ports and lumped ports is taken into account when the computing device  302  utilizes the resulting S-parameter model with any future mixed-port type of excitations. 
     In  FIG. 6 , a system diagram of an example of an implementation of an equivalent S-parameter network  600  of the plane wave port set-up of the parallel plate waveguide model  500  is shown in accordance with the present disclosure. In this example, the equivalent S-parameter network  600  is shown as an eight (8) port network having the pair of waveguide ports (i.e., the first waveguide port  506  and the second waveguide port  508 ) and the six (6) lumped ports (i.e., the first lumped port  522 , the second lumped port  524 , the third lumped port  526 , the fourth lumped port  528 , the fifth lumped port  530 , and the sixth lumped port  532 ). 
     It is appreciated by those of ordinary skill in the art that utilizing the equivalent S-parameter network  600  is preferable in modeling the electromagnetic characteristics of the vehicle  124  because scattering variables and scattering parameters (i.e., S-parameters) are especially useful in dealing with microwave circuits since S-parameters relate to signal flow rather than to voltages and currents directly. Moreover, S-parameters are preferred for characterizing microwave circuits because S-parameters are measured in a matched impedance system, in contrast to the open-circuit type and short-circuit type of measurements required for other available network parameters that can be very difficult to implement at microwave frequencies. 
     For a generic multi-port network, where the i-th ports are numbered from i=1 to N, where Nis the total number of ports, the scattering variables at a given port are defined in terms of the port voltage V i , port current I i , and a normalized characteristic impedance Z 0 . In general, the voltage and current at an i-th port may have their own phase angle relative to some previously established reference phase and may be described by
 
 V   i   =|V   i |angle θ and  I   i   =|I   i |angle Ø.
 
     As such, the average power flowing into the i-th port is then defined as
 
 P   i   =|V   i   ∥I   i |cos(θ−Ø).
 
     Therefore, for the i-th port, the associated S-parameter definition is in terms of incident and reflected “power waves” that are known as an incident scattering variable a i  and reflected scattering variable b i , defined by 
     
       
         
           
             
               
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     In this example, the incident scattering variable a i  and reflected scattering variable b i , are vectors {right arrow over (a)} and  b  and the S-parameters are elements of a scattering matrix {right arrow over (S)} that is defined by  b ={right arrow over (S)}·{right arrow over (a)}. Utilizing explicit components, this may also be expressed as 
     
       
         
           
             
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     As such, the relationship between the reflected (i.e., reflected scattering variable b i ) and incident power waves (incident scattering variable a i ) at each port of the multi-port network is expressed in terms of the multi-port network&#39;s individual S-parameters (i.e., S 11  to S ii ). The individual S-parameters may be measured when the multi-port network is impedance matched for zero reflections for a given port that is being measured, where the multi-port network is impedance matched by terminating the other ports with matching terminations that eliminate the reflections on the terminated ports. 
     In this example, the equivalent S-parameter network  600  is an eight (8) port network where two ports correspond to the first waveguide port  506  and second waveguide port  508  and six (6) lumped ports  522 ,  524 ,  526 ,  528 ,  530 , and  532  as shown on the vehicle model  316  in  FIG. 5 . The equivalent S-parameter network  600  represents the S-parameter model for the vehicle model  316  generated by the method  400  in step  402 . As such, the equivalent S-parameter network  600  may be utilized in executing the simulation of the method  400  in step  406 . In this example, the equivalent S-parameter network  600  is the S-parameter model that is stored in the storage  304 . 
     In general, the process of generating  402  the S-parameter model may be computationally intensive. For example, the computing device  302  may take a few days of computation time and require a large amount of memory  308  (as an example, tens of gigabytes in size) to perform the method  400  steps of  408  through  418 . However, once the S-parameter model (i.e., equivalent S-parameter network  600 ) is created, the equivalent S-parameter network  600  may be a relatively small (e.g., less than tens of megabytes in size). The computing device  302  may then utilize the equivalent S-parameter network  600  to run various transient analysis quickly that may be, for example, less than a few minutes of computation time. 
     The computing device  302  may run these various transient analyses by connecting circuit/system elements to the S-parameter ports (i.e., the first waveguide port  506 , the second waveguide port  508 , and the lumped ports  522 ,  524 ,  526 ,  528 ,  530 , and  532 ) of the equivalent 5-parameter network  600 . The computing device  302  may then set up excitation terminals at the 5-parameter ports in a transient circuit simulation tool, where the scaling factor has been applied to the waveform amplitudes of the first waveguide port  506  and the second waveguide port  508  to emulate the plane wave illumination of the vehicle  124 . The computing device  302  then may run a time-domain circuit simulation and then retrieve the results. In this example, the resulting waveforms in the voltages and currents observed at the electrical terminals of the equivalent 5-parameter network  600  (produced by the simulation tool) represent the complete system responses under a user-specified plane wave waveform impinging upon the vehicle model  316 . 
     As a result, utilizing the disclosed system and method allows for a large saving in computer processing time since there is no need to run a complex 3D field solver on an outdoor range for each different incident plane waveform or data/power waveform scenario. Moreover, the present approach allows for the use of fast circuit/system simulation tools. Furthermore, utilizing the present approach allows for all the 3D electromagnetic interactions for on-board components, devices, modules, or system under HIRF/EMP with specific plane wave incidence scenarios to be captured in compact S-parameter data files instead of large field solver data. This allows the S-parameter data files to be readily re-usable in circuit/system level simulations at later times and the resulting data does not occupy large amounts of storage space. 
     It will be understood that various aspects or details of the disclosure may be changed without departing from the scope of the disclosure. It is not exhaustive and does not limit the claimed disclosures to the precise form disclosed. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpose of limitation. Modifications and variations are possible in light of the above description or may be acquired from practicing the disclosure. The claims and their equivalents define the scope of the disclosure. Moreover, although the techniques have been described in language specific to structural features and/or methodological acts, it is to be understood that the appended claims are not necessarily limited to the features or acts described. Rather, the features and acts are described as example implementations of such techniques. 
     Further, the disclosure comprises embodiments according to the following clauses. 
     Clause 1. A method for modeling electromagnetic characteristics of a vehicle having electrical components, the method comprising: generating a parallel plate waveguide model having a first waveguide port and a second waveguide port; inserting a vehicle model for the vehicle within the parallel plate waveguide model, wherein the vehicle model has a plurality of lumped ports corresponding to the electrical components on-board the vehicle; executing an electromagnetic field solver on the first waveguide port, the second waveguide port, and the plurality of lumped ports, wherein the electromagnetic field solver is executed on the first waveguide port, the second waveguide port, and the plurality of lumped ports, and wherein the electromagnetic field solver produces a first output data; determining a scaling factor between a first power level configured to excite the first waveguide port and the second waveguide port and a second power level configured to excite the plurality of lumped ports; producing a scattering parameter (S-parameter) model for the vehicle from the first output data, wherein the S-parameter model includes a plurality of S-parameter ports; generating a plurality of excitation signals at the plurality of S-parameter ports, wherein the scaling factor has been applied to the plurality of excitation signals; and executing a time-domain circuit simulation to model the electromagnetic characteristics of the vehicle. 
     Clause 2. The method of clause 1, wherein the vehicle model is predetermined. 
     Clause 3. The method of clauses 1 or 2, further comprising saving the S-parameter model in a storage, wherein the S-parameter model is reusable for executing a system level transient simulation utilizing the S-parameter model. 
     Clause 4. The method of clause 3, wherein the S-parameter model is saved in the storage as a touchstone file. 
     Clause 5. The method of clauses 3 or 4, further comprising retrieving the S-parameter model from the storage prior to generating the plurality of excitation signals. 
     Clause 6. The method of clauses 1, 2, 3, 4, or 5, wherein each lumped port of the plurality of lumped ports is configured to have electrical properties corresponding to an on-board system of the vehicle and wherein the first waveguide port and the second waveguide port are configured to simulate a plane wave illumination of the vehicle. 
     Clause 7. The method of clauses 1, 2, 3, 4, 5, or 6, wherein the second power level is approximately 0.5 Watts and the first power level is determined based a cross-section of a waveguide defined by the parallel plate waveguide model and an incident plane wave generated by the electromagnetic field solver at the first waveguide port or the second waveguide port. 
     Clause 8. The method of clauses 1, 2, 3, 4, 5, 6, or 7, wherein the generating the plurality of excitation signals at the plurality of S-parameter ports includes connecting a circuit element to each S-parameter port to generate an excitation signal. 
     Clause 9. A system for modeling electromagnetic characteristics of a vehicle, the system comprising: a memory; one or more processors; a computer-readable medium in the memory, the computer-readable medium storing instructions that, when executed by the one or more processors, cause the system to perform operations comprising: generating a parallel plate waveguide model having a first waveguide port and a second waveguide port; inserting a vehicle model for the vehicle within the parallel plate waveguide model, wherein the vehicle model has a plurality of lumped ports corresponding to electrical components on-board the vehicle; executing an electromagnetic field solver on the first waveguide port, the second waveguide port, and the plurality of lumped ports, wherein the electromagnetic field solver is executed on the first waveguide port, the second waveguide port, and the plurality of lumped ports, and wherein the electromagnetic field solver produces a first output data; determining a scaling factor between a first power level configured to excite the first waveguide port and the second waveguide port, and a second power level configured to excite the plurality of lumped ports; producing a scattering parameter (S-parameter) model for the vehicle from the first output data, wherein the S-parameter model includes a plurality of S-parameter ports; generating a plurality of excitation signals at the plurality of S-parameter ports, wherein the scaling factor has been applied to the plurality of excitation signals; and executing a time-domain circuit simulation to model the electromagnetic characteristics of the vehicle. 
     Clause 10. The system of clause 9, wherein the vehicle model is predetermined. 
     Clause 11. The system of clauses 9 or 10, wherein the system is further configured to perform the operation of saving the S-parameter model in a storage, wherein the S-parameter model is reusable for executing a system level transient simulation utilizing the S-parameter model. 
     Clause 12. The system of clause 11, wherein the S-parameter model is saved in the storage as a touchstone file. 
     Clause 13. The system of clauses 11 or 12, wherein the system is further configured to perform the operation of retrieving the S-parameter model from the storage prior to generating the plurality of excitation signals. 
     Clause 14. The system of clauses 9, 10, 11, 12, or 13, wherein each lumped port of the plurality of lumped ports is configured to have electrical properties corresponding to an on-board component of the vehicle and wherein the first waveguide port and the second waveguide port are configured to simulate a plane wave illumination of the vehicle. 
     Clause 15. The system of clauses 9, 10, 11, 12, 13, or 14, wherein the second power level is approximately 0.5 Watts and the first power level is determined based a cross-section of a waveguide defined by the parallel plate waveguide model and an incident plane wave generated by the electromagnetic field solver at the first waveguide port or the second waveguide port. 
     Clause 16. The system of clauses 9, 10, 11, 12, 13, 14, or 15, wherein the generating the plurality of excitation signals at the plurality of S-parameter ports includes connecting a circuit element to each S-parameter port to generate an excitation signal. 
     Clause 17. A method for modeling electromagnetic characteristics of a vehicle having electrical components, the method comprising: generating a scattering parameter (S-parameter) model for the vehicle utilizing a parallel plate waveguide model having a first waveguide port and a second waveguide port and a vehicle model having a plurality of lumped ports corresponding to the electrical components on-board the vehicle; determining a scaling factor between a first power level utilized to excite the first and second waveguide ports and a second power level utilized to excite the plurality of lumped ports; executing a system level transient simulation utilizing the S-parameter model for the vehicle and the scaling factor. 
     Clause 18. The method of clause 17, wherein the generating the S-parameter model comprises: generating the parallel plate waveguide model; inserting the vehicle model for the vehicle within the parallel plate waveguide model; and executing an electromagnetic field solver on the first waveguide port, the second waveguide port, and the plurality of lumped ports, wherein the electromagnetic field solver is executed on the first waveguide port, the second waveguide port, and the plurality of lumped ports, and wherein the electromagnetic field solver produces a first output data; and producing the S-parameter model for the vehicle from the first output data, wherein the S-parameter model includes a plurality of S-parameter ports. 
     Clause 19. The method of clauses 18, wherein the vehicle model is predetermined. 
     Clause 20. The method of clauses 18 or 19, wherein the executing of the system level transient simulation comprises: generating a plurality of excitation signals at the plurality of S-parameter ports, wherein the scaling factor has been applied to the plurality of excitation signals; and executing a time-domain circuit simulation to model the electromagnetic characteristics of the vehicle. 
     To the extent that terms “includes,” “including,” “has,” “contains,” and variants thereof are used herein, such terms are intended to be inclusive in a manner similar to the term “comprises” as an open transition word without precluding any additional or other elements. Moreover, conditional language such as, among others, “can,” “could,” “might” or “may,” unless specifically stated otherwise, are understood within the context to present that certain examples include, while other examples do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that certain features, elements and/or steps are in any way required for one or more examples or that one or more examples necessarily include logic for deciding, with or without user input or prompting, whether certain features, elements and/or steps are included or are to be performed in any particular example. Conjunctive language such as the phrase “at least one of X, Y or Z,” unless specifically stated otherwise, is to be understood to present that an item, term, etc. may be either X, Y, or Z, or a combination thereof. 
     In some alternative examples of implementations, the function or functions noted in the blocks may occur out of the order noted in the figures. For example, in some cases, two blocks shown in succession may be executed substantially concurrently, or the blocks may sometimes be performed in the reverse order, depending upon the functionality involved. Also, other blocks may be added in addition to the illustrated blocks in a flowchart or block diagram. Moreover, the operations of the example processes are illustrated in individual blocks and summarized with reference to those blocks. The processes are illustrated as logical flows of blocks, each block of which can represent one or more operations that can be implemented in hardware, software, or a combination thereof. In the context of software, the operations represent computer-executable instructions stored on one or more computer-readable medium that, when executed by one or more processing units, enable the one or more processing units to perform the recited operations. Generally, computer-executable instructions include routines, programs, objects, modules, components, data structures, and the like that perform particular functions or implement particular abstract data types. The order in which the operations are described is not intended to be construed as a limitation, and any number of the described operations can be executed in any order, combined in any order, subdivided into multiple sub-operations, and/or executed in parallel to implement the described processes. The described processes can be performed by resources associated with one or more device(s) such as one or more internal or external CPUs or GPUs, and/or one or more pieces of hardware logic such as FPGAs, DSPs, or other types of accelerators. 
     All of the methods and processes described above may be embodied in, and fully automated via, software code modules executed by one or more general purpose computers or processors. The code modules may be stored in any type of computer-readable storage medium or other computer storage device. Some or all of the methods may alternatively be embodied in specialized computer hardware.