Pub Date : 1985-08-01DOI: 10.1109/ISEMC.1985.7566957
A. Fraser-Smith, R. Helliwell
S tanford University is currently conducting a global survey of electromagnetic noise in the 10 32,000 Hz (ELF/V LF) frequency band using a network of eight computer-controlled receiving systems, or ‘radiom eters.’ One goal of this m easurem ent program is to improve communication in the E L F/V L F band by providing more upto-date and complete inform ation about the properties of E L F/V L F noise (both na tu ra l and man-made) than is currently available—the last extensive survey of noise in the same frequency band was made over two decades ago. In this p resentation we describe the Stanford E L F /V L F noise m easurem ent project, including the instrum enta tion comprising each of the radiometers, the form of the ir analog and digital m easurem ents (which are made under the control of a minicomputer), and the d a ta processing techniques th a t will be used. T he results of previous noise surveys are briefly reviewed and the significance of the overall decline of noise power with increasing frequency revealed by these surveys and other studies is discussed in the context of the scientific applications of the noise d a ta obtained by the radiom eter network.
目前，美国斯坦福大学正在利用由8个计算机控制的接收系统或“射频计”组成的网络，对10 32000赫兹(ELF/V LF)频段的电磁噪声进行全球调查。“这项测量计划的一个目标是通过提供更多最新和完整的关于E - L - F/V - L - F噪声特性的信息(包括自然和人为的)来改善E - L - F/V - L - F波段的通信，而不是目前可用的-上一次对同一频段的噪声进行广泛调查是在20多年前进行的。”在本报告中，我们描述了斯坦福E - L - F /V - L - F噪声测量项目，包括由每个辐射计组成的仪器，模拟和数字测量的形式(在一台小型计算机的控制下进行)，以及将使用的数据处理技术。本文简要回顾了以往的噪声调查结果，并结合辐射计网获得的噪声数据的科学应用，讨论了这些调查和其他研究所揭示的噪声功率随频率增加而总体下降的意义。
{"title":"The Stanford University ELF/VLF Radiometer Project: Measurement of the Global Distribution of ELF/VLF Electromagnetic Noise","authors":"A. Fraser-Smith, R. Helliwell","doi":"10.1109/ISEMC.1985.7566957","DOIUrl":"https://doi.org/10.1109/ISEMC.1985.7566957","url":null,"abstract":"S tanford University is currently conducting a global survey of electromagnetic noise in the 10 32,000 Hz (ELF/V LF) frequency band using a network of eight computer-controlled receiving systems, or ‘radiom eters.’ One goal of this m easurem ent program is to improve communication in the E L F/V L F band by providing more upto-date and complete inform ation about the properties of E L F/V L F noise (both na tu ra l and man-made) than is currently available—the last extensive survey of noise in the same frequency band was made over two decades ago. In this p resentation we describe the Stanford E L F /V L F noise m easurem ent project, including the instrum enta tion comprising each of the radiometers, the form of the ir analog and digital m easurem ents (which are made under the control of a minicomputer), and the d a ta processing techniques th a t will be used. T he results of previous noise surveys are briefly reviewed and the significance of the overall decline of noise power with increasing frequency revealed by these surveys and other studies is discussed in the context of the scientific applications of the noise d a ta obtained by the radiom eter network.","PeriodicalId":256770,"journal":{"name":"1985 IEEE International Symposium on Electromagnetic Compatibility","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116387772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-08-01DOI: 10.1109/ISEMC.1985.7566969
R. Balestri, Roxanne Brown
A direct adaptive time domain noise cancellation technique has been developed and applied to measured fast EM transient response data. The filter perfor mance is determined by processing data and transforming the residual signal and error terms into the frequency domain. When applied to actual data, the range of usable data is extended to higher frequencies, and a direct estimate of the signal-to-noise ratio as a function of frequency is obtained. The use of the noise cancellation process not only extends the useful range in the frequency domain, but additionally provides the upper frequency limit for use of measured responses. I . INTRODUCTION Adaptive noise cancellation techniques have been applied to a wide variety of processes. The simplest technique conceptually is known as the Widrow LMS [1], [2] (Least Mean Square) technique. The procedure has been widely applied with the notable absence of applications to fast transient electromagnetic pulse data where the potential benefits are significant. The primary differences between previous applica tions and those presented in this paper relate to the bandwidth of the signal, the environment-induced noise, the measurement noise, and the concatenation of time segments into a single signal record. The objective here is to develop a robust algorithm which will handle data with widely varying properties as opposed to the development of a statistically robust signal processing procedure. Section II of this paper describes the measurement process and illustrates the range of data types requiring processing. Section III presents a brief derivation of the LMS filter with some heuristic arguments considered for the algorithms selected for investigation. Section IV consists of plots of the test signals used for the study, along with plots of the filtered signals and noise signals in the frequency domain. Section V presents the conclusions obtained from the filter study. II. MEASUREMENT PROCESS AND NOISE CHARACTERISTICS The measurement process and equipment is illustra ted in Figure 1 . The probe balun and fiber optic transmitter are usually exposed to the incident field resulting in a transient environment-induced noise signal. Examples of this noise signal are presented in Figure 2. The data in Figure 2 was obtained with a terminated balun and represents signal coupled directly to the exposed instrumentation system. The coupling of a derivative effect is clearly discernable in Figures 2a and 2b. Figure 2c is an identical setup with a 36 dB attenuation of the fiber optic transmitter output. The power spectrum density of the signals is presented in Figure 3The second source of noise occurs in the digitiza tion process. This process is usually carried out by three or four separate digitizers with intensity and sweep speed settings appropriate for the particular portion of the waveform being recorded. Free running digitizer output is illustrated in Figure 4. In this case, the digitizer is effectively recor
{"title":"Adaptive Time Domain Noise Cancellation for EMP Measurements","authors":"R. Balestri, Roxanne Brown","doi":"10.1109/ISEMC.1985.7566969","DOIUrl":"https://doi.org/10.1109/ISEMC.1985.7566969","url":null,"abstract":"A direct adaptive time domain noise cancellation technique has been developed and applied to measured fast EM transient response data. The filter perfor mance is determined by processing data and transforming the residual signal and error terms into the frequency domain. When applied to actual data, the range of usable data is extended to higher frequencies, and a direct estimate of the signal-to-noise ratio as a function of frequency is obtained. The use of the noise cancellation process not only extends the useful range in the frequency domain, but additionally provides the upper frequency limit for use of measured responses. I . INTRODUCTION Adaptive noise cancellation techniques have been applied to a wide variety of processes. The simplest technique conceptually is known as the Widrow LMS [1], [2] (Least Mean Square) technique. The procedure has been widely applied with the notable absence of applications to fast transient electromagnetic pulse data where the potential benefits are significant. The primary differences between previous applica tions and those presented in this paper relate to the bandwidth of the signal, the environment-induced noise, the measurement noise, and the concatenation of time segments into a single signal record. The objective here is to develop a robust algorithm which will handle data with widely varying properties as opposed to the development of a statistically robust signal processing procedure. Section II of this paper describes the measurement process and illustrates the range of data types requiring processing. Section III presents a brief derivation of the LMS filter with some heuristic arguments considered for the algorithms selected for investigation. Section IV consists of plots of the test signals used for the study, along with plots of the filtered signals and noise signals in the frequency domain. Section V presents the conclusions obtained from the filter study. II. MEASUREMENT PROCESS AND NOISE CHARACTERISTICS The measurement process and equipment is illustra ted in Figure 1 . The probe balun and fiber optic transmitter are usually exposed to the incident field resulting in a transient environment-induced noise signal. Examples of this noise signal are presented in Figure 2. The data in Figure 2 was obtained with a terminated balun and represents signal coupled directly to the exposed instrumentation system. The coupling of a derivative effect is clearly discernable in Figures 2a and 2b. Figure 2c is an identical setup with a 36 dB attenuation of the fiber optic transmitter output. The power spectrum density of the signals is presented in Figure 3The second source of noise occurs in the digitiza tion process. This process is usually carried out by three or four separate digitizers with intensity and sweep speed settings appropriate for the particular portion of the waveform being recorded. Free running digitizer output is illustrated in Figure 4. In this case, the digitizer is effectively recor","PeriodicalId":256770,"journal":{"name":"1985 IEEE International Symposium on Electromagnetic Compatibility","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127142694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-08-01DOI: 10.1109/ISEMC.1985.7566961
W. Chisholm, P. Guillo, W. Janischewskyj, D. S. Andrews
Lightning stroke location systems based on magnetic direction finding can provide measurements o f peak radiated field. Several tools used to study this peak radiated field data are described. These tools include (1) methods fo r using redundant bearing and am plitude data to reduce various erro rs; (2) methods for obtaining unbiased estim ates o f stroke am plitude and its variance; (3) methods for inferring the correct family of statistical distribution for the peak radiated field data. A com parison is made o f data from N orthern O ntario w ith similar data from Florida, Oklahoma and the E astern U.S.A.
{"title":"Analytical and Statistical Tools for Studies of Lightning-Radiated Fields","authors":"W. Chisholm, P. Guillo, W. Janischewskyj, D. S. Andrews","doi":"10.1109/ISEMC.1985.7566961","DOIUrl":"https://doi.org/10.1109/ISEMC.1985.7566961","url":null,"abstract":"Lightning stroke location systems based on magnetic direction finding can provide measurements o f peak radiated field. Several tools used to study this peak radiated field data are described. These tools include (1) methods fo r using redundant bearing and am plitude data to reduce various erro rs; (2) methods for obtaining unbiased estim ates o f stroke am plitude and its variance; (3) methods for inferring the correct family of statistical distribution for the peak radiated field data. A com parison is made o f data from N orthern O ntario w ith similar data from Florida, Oklahoma and the E astern U.S.A.","PeriodicalId":256770,"journal":{"name":"1985 IEEE International Symposium on Electromagnetic Compatibility","volume":"145 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129040440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-08-01DOI: 10.1109/ISEMC.1985.7566913
Val L. Erwin, K. Fischer
An unaccep tab le increase in the rad ia ted emissions am plitudes of an e lectron ic d a ta processing product was a ttr ib u ted to m ultiple in teg ra ted -c ircu it (IC) sourcing. Conducted w aveform s genera ted by these devices on the data /add ress bus w ere m easured in the tim e domain. Emissions rad ia ted from various IC sources w ere m easured in the frequency domain a t an open-field te s t site . Interchanging ICs, even though of a sam e device type, had a significant im pact upon th e EMC profile.
{"title":"Radiated-Emission Ramifications of Multiple IC Sourcing","authors":"Val L. Erwin, K. Fischer","doi":"10.1109/ISEMC.1985.7566913","DOIUrl":"https://doi.org/10.1109/ISEMC.1985.7566913","url":null,"abstract":"An unaccep tab le increase in the rad ia ted emissions am plitudes of an e lectron ic d a ta processing product was a ttr ib u ted to m ultiple in teg ra ted -c ircu it (IC) sourcing. Conducted w aveform s genera ted by these devices on the data /add ress bus w ere m easured in the tim e domain. Emissions rad ia ted from various IC sources w ere m easured in the frequency domain a t an open-field te s t site . Interchanging ICs, even though of a sam e device type, had a significant im pact upon th e EMC profile.","PeriodicalId":256770,"journal":{"name":"1985 IEEE International Symposium on Electromagnetic Compatibility","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131972207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-08-01DOI: 10.1109/ISEMC.1985.7567003
G. Brock, Tamie L. Bedford, G-M. Grange
It is well known that as computer programs become more complex, the user interface must be simplified to enhance the data interpretation. This paper will provide a brief overview of the Intrasystem Electromagnetic Compatibility Analysis Program called IEMCAP, and the improvements made by Kaman Sciences Corporation (KSC) to streamline the basic IEMCAP output. The composite electromagnetic compatibility (EMC) code will be referred to as the Intrasystem Electromagnetic Compatibility Analysis Program with Graphics (IEMCAP-G). The basic IEMCAP code and its output will be introduced, followed by a discussion of the improvements made to the IEMCAP output. The improvements include: output matrices, extraction of data, antenna position graphics, and line plots. These modifications aid the EMC engineer in determining potential electromagnetic interference (EMI) problems and their solutions.
{"title":"An Overview of the Intrasystem EMC Analysis Program with Graphics","authors":"G. Brock, Tamie L. Bedford, G-M. Grange","doi":"10.1109/ISEMC.1985.7567003","DOIUrl":"https://doi.org/10.1109/ISEMC.1985.7567003","url":null,"abstract":"It is well known that as computer programs become more complex, the user interface must be simplified to enhance the data interpretation. This paper will provide a brief overview of the Intrasystem Electromagnetic Compatibility Analysis Program called IEMCAP, and the improvements made by Kaman Sciences Corporation (KSC) to streamline the basic IEMCAP output. The composite electromagnetic compatibility (EMC) code will be referred to as the Intrasystem Electromagnetic Compatibility Analysis Program with Graphics (IEMCAP-G). The basic IEMCAP code and its output will be introduced, followed by a discussion of the improvements made to the IEMCAP output. The improvements include: output matrices, extraction of data, antenna position graphics, and line plots. These modifications aid the EMC engineer in determining potential electromagnetic interference (EMI) problems and their solutions.","PeriodicalId":256770,"journal":{"name":"1985 IEEE International Symposium on Electromagnetic Compatibility","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116738865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-08-01DOI: 10.1109/ISEMC.1985.7566971
W. J. Adams, J. G. Burbano, H. B. O Donnell
This paper analyzes the magnetic field coupling from System Generated Electromagnetic Pulse (SGEMP) in terminal protection devices (TPD's) to non-interface or buried circuits of spacecraft electronics boxes. The analysis approach is outlined and results obtained from a computer based solution of the analysis are presented along with test data collected to empirically verify the analysis. Finally an example is provided in which the analysis results are used to calculate the energy coupled to a buried circuit so that a comparison of known device pulse burn out levels can be made. This technique provides an assessment of device susceptibility to the induced fields for representative circuit board trace layouts.
{"title":"SGEMP Induced Magnetic Field Coupling to Buried Circuits","authors":"W. J. Adams, J. G. Burbano, H. B. O Donnell","doi":"10.1109/ISEMC.1985.7566971","DOIUrl":"https://doi.org/10.1109/ISEMC.1985.7566971","url":null,"abstract":"This paper analyzes the magnetic field coupling from System Generated Electromagnetic Pulse (SGEMP) in terminal protection devices (TPD's) to non-interface or buried circuits of spacecraft electronics boxes. The analysis approach is outlined and results obtained from a computer based solution of the analysis are presented along with test data collected to empirically verify the analysis. Finally an example is provided in which the analysis results are used to calculate the energy coupled to a buried circuit so that a comparison of known device pulse burn out levels can be made. This technique provides an assessment of device susceptibility to the induced fields for representative circuit board trace layouts.","PeriodicalId":256770,"journal":{"name":"1985 IEEE International Symposium on Electromagnetic Compatibility","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125260483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-08-01DOI: 10.1109/ISEMC.1985.7566934
M. Crawford, G. Koepke
This paper compares measurement r e s u l t s o b ta in ed using a 2 .7 m x 3.1 m x 4.6 m r e v e r b e r a t i o n chamber and a 4 .9 m x 6.7 m x 8 .5 m anechoic chamber t o determine t h e EM s u s c e p t i b i l i t y of equipment under t e s t (EUT). The frequency range was 200 MHz 18 GHz. The " c o r r e l a t i o n f a c t o r " between th e two te chn iq ues appea rs t o be d i r e c t l y p ro p o r t i o n a l t o t h e gain o f t h e EUT. Four sample EUTs inc luded in t h i s s tudy were a one c e n t im e te r d ip o l e probe , a r idged horn an t enna , a small r e c t a n g u l a r TEM t r a n sm is s io n c e l l with an a p e r t u r e and a modif ied 7 .0 cm (2 .75" ) d ia mete r fol ded f i n a i r c r a f t r o c k e t .
这篇文章比得上测量r e s t u l o b ta在艾德用2。7 m乘以3。1 x 4。6 m r e v r b t r a e i o n e室和a 4。9 m x 6。7乘以8。5 m anechoic室t o个重大t h e EM s u s c e p t i b i l i t y e s t (t下的设备EUT)。频率是200兆赫18千兆赫。“c e o r r l i o n f c t o t a r " th e两个te开航智商之间价值自己医院t c o d be i r e t l y p ro p o r t i o n a l t o t h e o f t h e EUT增益。四EUTs inc luded在样本t h i s s tudy是一号a c e n t te le e r d ip o l e探头,t a r idged霍恩an兹省,小r e a t c . n g u l a r TEM t r a n sm是io s n c e l l with an a p e r t u r e和a修正7。0厘米(2个简易爆炸装置。他花了75”)d腰果r fol的f - i - n - a r i c t r a f r o c k e t。
{"title":"Comparing EM Susceptibility Measurement Results Between Reverberation and Anechoic Chambers","authors":"M. Crawford, G. Koepke","doi":"10.1109/ISEMC.1985.7566934","DOIUrl":"https://doi.org/10.1109/ISEMC.1985.7566934","url":null,"abstract":"This paper compares measurement r e s u l t s o b ta in ed using a 2 .7 m x 3.1 m x 4.6 m r e v e r b e r a t i o n chamber and a 4 .9 m x 6.7 m x 8 .5 m anechoic chamber t o determine t h e EM s u s c e p t i b i l i t y of equipment under t e s t (EUT). The frequency range was 200 MHz 18 GHz. The \" c o r r e l a t i o n f a c t o r \" between th e two te chn iq ues appea rs t o be d i r e c t l y p ro p o r t i o n a l t o t h e gain o f t h e EUT. Four sample EUTs inc luded in t h i s s tudy were a one c e n t im e te r d ip o l e probe , a r idged horn an t enna , a small r e c t a n g u l a r TEM t r a n sm is s io n c e l l with an a p e r t u r e and a modif ied 7 .0 cm (2 .75\" ) d ia mete r fol ded f i n a i r c r a f t r o c k e t .","PeriodicalId":256770,"journal":{"name":"1985 IEEE International Symposium on Electromagnetic Compatibility","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133455853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-08-01DOI: 10.1109/ISEMC.1985.7566994
S. Mishra, S. Kashyap, R. Balaberda
Results of experimental investigations to study the input impedance of antennas contained within enclosures are presented. The data includes mea sured impedance of a variety of antennas commonly used as probes or radiating sources in e.m. emission and susceptibility measurements. The enclosures studied include "TEM" cells, resonant shielded enclosures and absorber lined chambers. Measure ments were also made on an "open-field" site for comparison purposes.
{"title":"Input Impedance of Antennas Inside Enclosures","authors":"S. Mishra, S. Kashyap, R. Balaberda","doi":"10.1109/ISEMC.1985.7566994","DOIUrl":"https://doi.org/10.1109/ISEMC.1985.7566994","url":null,"abstract":"Results of experimental investigations to study the input impedance of antennas contained within enclosures are presented. The data includes mea sured impedance of a variety of antennas commonly used as probes or radiating sources in e.m. emission and susceptibility measurements. The enclosures studied include \"TEM\" cells, resonant shielded enclosures and absorber lined chambers. Measure ments were also made on an \"open-field\" site for comparison purposes.","PeriodicalId":256770,"journal":{"name":"1985 IEEE International Symposium on Electromagnetic Compatibility","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131817730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-08-01DOI: 10.1109/ISEMC.1985.7566924
Cleveland F. Watkins
ANSI C95.1-1982 establishes safety levels and guidelines with respect to human exposure to electromagnetic fields in the frequency range 300 kHz to 100 GHz, Nomograms have been developed for deter mining safe distances based on the familiar far-field equivalent plane-wave power density equation. How ever, for linear-type antennas, distances that were obtained which were less than about one-sixth (X/6) wavelength may not necessarily assure a "safe" dis tance. In these cases, other methods must be used to determine the field strengths from which appropriate distances could be determined. By using previously determined far-field "safe" distances, other nomo grams have been developed to determine "safe" dis tances for these near-field conditions. Example curves of normalized electric field intensities are used for developing the nomograms. These nomograms can be used to determine near-field distances for any other criteria for which far-field distances have been determined. The appendix describes the tech nique for developing the nomograms and could be fol lowed for developing nomograms from other curves where far-field distances need to be corrected for near-field conditions.
{"title":"A Technique for Determining Safe Separation Distances for Personnel and Electronic Equipment in the Near-Field of Short Dipole Antennas A Graphical Method - Its Development and Use","authors":"Cleveland F. Watkins","doi":"10.1109/ISEMC.1985.7566924","DOIUrl":"https://doi.org/10.1109/ISEMC.1985.7566924","url":null,"abstract":"ANSI C95.1-1982 establishes safety levels and guidelines with respect to human exposure to electromagnetic fields in the frequency range 300 kHz to 100 GHz, Nomograms have been developed for deter mining safe distances based on the familiar far-field equivalent plane-wave power density equation. How ever, for linear-type antennas, distances that were obtained which were less than about one-sixth (X/6) wavelength may not necessarily assure a \"safe\" dis tance. In these cases, other methods must be used to determine the field strengths from which appropriate distances could be determined. By using previously determined far-field \"safe\" distances, other nomo grams have been developed to determine \"safe\" dis tances for these near-field conditions. Example curves of normalized electric field intensities are used for developing the nomograms. These nomograms can be used to determine near-field distances for any other criteria for which far-field distances have been determined. The appendix describes the tech nique for developing the nomograms and could be fol lowed for developing nomograms from other curves where far-field distances need to be corrected for near-field conditions.","PeriodicalId":256770,"journal":{"name":"1985 IEEE International Symposium on Electromagnetic Compatibility","volume":"108 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1985-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134275837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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