Comparison of theoretical and practical forward power requirements during CS114 calibration as per MIL STD 461E F
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2015 13th International Conference on Electromagnetic Interference and Compatibility (INCEMIC) Comparison of Theoretical and Practical Forward power requirements during CS114 calibration as per MIL STD 461E/F W. Bilal Khan L. Sudhakar ASTRA MICROWAVE PRODUCTS LTD., Plot No: 18 -21, Imarath Kancha, Hardware Park, Raviryala Village, Maheshwaram Mandal, R.R District, AP 500 005, India Phone: 040 3061 8777, Fax: 040 3061 8748 Email: bilalkhan.w@astramwp.com Abstract - Military EMC standard specifies the need of CS114 - conducted susceptibility testing in the frequency range of 10 kHz to 200 MHz using bulk cable injection method. This requirement is applicable to all interconnecting cables including power cables. The Equipment Under Test (EUT) shall not exhibit any malfunction, degradation of performance, or deviation from specified indications beyond the tolerances indicated in the individual equipment specifications, when subjected to an injection probe drive level which has been pre-calibrated to the appropriate current limit. This paper compares the theoretical and practical required forward power to meet the current limit as specified in MIL STD 461E/F standards. This paper points out the required forward power depends duly on proper selection of the Current Injection probes with their associated insertion loss instead adapting for high wattage power amplifiers. has been found to be necessary to obtain consistency in test results. Insertion loss is measured as shown in Fig 2. It is the difference in dB of the power applied to the probe installed in the calibration fixture and the power level detected by the measurement receiver. I. INTRODUCTION Fig 1. Insertion loss characteristics of injection probes The basic concept of Bulk Current Injection (BCI) test is to simulate currents that will be developed on platform cabling from electromagnetic fields generated by antenna transmissions both on and off the platform. This type of test is often considered as a bulk current test since current is the parameter measured. However, it is important to note that the test signal is inductively coupled and that Faraday's law predicts an induced voltage in a circuit loop with the resultant current flow and voltage distribution dependent on the various impedances present. ŽĂdžŝĂůůŽĂĚ /ŶũĞĐƚŝŽŶ WƌŽďĞ ^ŝŐŶĂů 'ĞŶĞƌĂƚŽƌ ĂůŝďƌĂƚŝŽŶ II. INSERTION LOSS MEASUREMENT FOR BCI PROBE DĞĂƐƵƌĞŵĞŶƚ Fig 1 shows the Insertion loss characteristics of injection probes as defined in MIL-STD-461E [1] and MIL-STD-461F [2] standard. A control on insertion loss &ŝdžƚƵƌĞ ZĞĐĞŝǀĞƌ Fig 2. Setup for Insertion Loss measurement ϵϳϴͲϭͲϱϬϵϬͲϱϯϱϬͲϲͬϭϱͬΨϯϭ͘ϬϬΞϮϬϭϱ/ 1 Authorized licensed use limited to: Blue Origin LLC. Downloaded on January 22,2023 at 05:24:19 UTC from IEEE Xplore. Restrictions apply. III. CS114 ± BULK CURRENT INJECTION CALIBRATION order to achieve the curve #5 limit current is measured and plotted using the software. Fig 5 shows the theoretical and actual required forward power comparison graph. The difference between the two measurements is found to be almost equal below 1MHz and 2 to 3W increase in power level is observed above 1MHz in actual measurement. The test limit current (dBμA) as shown in Fig 3 is calibrated by recording the forward power required to meet the limit current on a 50 ohm calibration fixture for each frequency in a defined step size. The calibration fixture with terminations is a 50 ohm transmission line. Since the injection probe is around the center conductor within the fixture, a signal is being induced in the loop formed by the center conductor, the two 50 ohm loads, and the structure of the fixture to which the 50 ohm loads are terminated. Measurement of induced current levels is performed by measuring a corresponding voltage across one of the 50 ohm loads. Since the 50 ohm loads are in series for the induced signal, the total drive voltage is actually two times that being measured [Criteria 1]. ^ŝŐŶĂů 'ĞŶĞƌĂƚŽƌ ŽĂdžŝĂů>ŽĂĚ /ŶũĞĐƚŝŽŶ ŵƉůŝĨŝĞƌ WƌŽďĞ ŝƌĞĐƚŝŽŶĂů ŽƵƉůĞƌ DĞĂƐƵƌĞŵĞŶƚ ĂůŝďƌĂƚŝŽŶ &ŝdžƚƵƌĞ ƚƚĞŶƵĂƚŽƌ ZĞĐĞŝǀĞƌ DĞĂƐƵƌĞŵĞŶƚ ZĞĐĞŝǀĞƌ Fig 3. CS114 Current limit for curve #5 Fig 4. CS114 Calibration Setup Table 1 illustrates the comparison between theoretical and practical forward power requirements for curve #5 severity level. The Freq. with respect to the limit current is plotted from 10 kHz ± 200 MHz. The Injection probe (Model. IP-DR250) and Calibration fixture (Model. CJDR250) of PRANA was used. Column B gives the Insertion loss measured as per the Fig 2. Column C denotes the limit current in dBμA. The target level at the Receiver input ± Column D is calculated by using the formula [dBm = (dBμA + 20*log*50) ± 107] where 50 denotes the 50ohm impedance of the calibration fixture. The required injection power ± Column E is then calculated by compensating the Insertion loss reading to the target level at the Receiver. The obtained forward power level in dBm is converted to watts as shown in Column F. Fig 5. Required Forward Power Comparison Graph The practical CS114 calibration measurement was performed as per the Fig 4 using EMC32 EMS automation software. The required forward power level in watts in In many EMC laboratories, it is often advisable to use the RF attenuator between the injection probe and amplifier to protect the amplifier from VSWR and 2 Authorized licensed use limited to: Blue Origin LLC. Downloaded on January 22,2023 at 05:24:19 UTC from IEEE Xplore. Restrictions apply. Table 1 Comparison of Theoretical and Practical Forward Power Requirements &ƌĞƋƵĞŶĐLJ ;D,njͿ dLJƉŝĐĂů /WƌŽďĞ /ŶƐĞƌƚŝŽŶ>ŽƐƐ ;ĚͿ >ŝŵŝƚƵƌƌĞŶƚ ƵƌǀĞηϱ ;ĚђͿ dĂƌŐĞƚ>ĞǀĞů ĂƚZĞĐĞŝǀĞƌ ŝŶƉƵƚ;ĚŵͿ dLJƉŝĐĂů ZĞƋƵŝƌĞĚ &ŽƌǁĂƌĚ WŽǁĞƌ;ĚŵͿ dLJƉŝĐĂů ZĞƋƵŝƌĞĚ&ŽƌǁĂƌĚ WŽǁĞƌ;tͿ ǁŝƚŚϬĚƉĂĚ & ĐƚƵĂů ZĞƋƵŝƌĞĚ&ŽƌǁĂƌĚ WŽǁĞƌ;tͿ ǁŝƚŚϬĚƉĂĚ ' ĐƚƵĂů ZĞƋƵŝƌĞĚ&ŽƌǁĂƌĚ WŽǁĞƌ;tͿ ǁŝƚŚϯĚƉĂĚ , Ϭ͘Ϭϭ Ϭ͘ϬϮ Ϭ͘Ϭϯ Ϭ͘Ϭϰ Ϭ͘Ϭϱ Ϭ͘Ϭϲ Ϭ͘Ϭϳ Ϭ͘Ϭϴ Ϭ͘Ϭϵ Ϭ͘ϭ Ϭ͘Ϯ Ϭ͘ϯ Ϭ͘ϰ Ϭ͘ϱ ϭ ϱ ϭϬ ϮϬ ϯϬ ϰϬ ϱϬ ϲϬ ϳϬ ϴϬ ϵϬ ϭϬϬ ϭϭϬ ϭϮϬ ϭϯϬ ϭϰϬ ϭϱϬ ϭϲϬ ϭϳϬ ϭϴϬ ϭϵϬ ϮϬϬ ϯϭ͘ϲ Ϯϳ͘ϲ Ϯϰ͘ϭ Ϯϭ͘ϲ ϭϵ͘ϳ ϭϴ͘ϭ ϭϲ͘ϵ ϭϱ͘ϵ ϭϱ ϭϰ͘Ϯ ϵ͘ϳ ϳ͘Ϯϵ ϱ͘Ϯ ϯ͘ϳϮ ϲ͘Ϭϵ ϰ͘ϲϲ ϯ͘ϲϱ Ϯ͘ϴϰ Ϯ͘ϯϰϱ Ϯ͘ϭϱ Ϯ͘ϬϮ ϭ͘ϵϴ Ϯ͘ϭ Ϯ͘ϯϯ Ϯ͘ϳϭ ϯ ϯ͘Ϭϰ Ϯ͘ϵϵ Ϯ͘ϴϰ Ϯ͘ϴϭ ϯ͘Ϭϰ ϯ͘ϱϴ ϰ͘ϯϵ ϱ͘Ϭϳ ϱ͘ϰϯ ϱ͘ϰϱ ϲϵ͘Ϯ ϳϱ͘ϯ ϳϴ͘ϵ ϴϬ͘ϵ ϴϯ͘ϭ ϴϱ͘ϭ ϴϲ͘ϭ ϴϳ͘ϯ ϴϴ͘ϭ ϴϴ͘ϵ ϵϱ͘Ϭ ϵϴ͘ϵ ϭϬϭ͘Ϯ ϭϬϯ͘ϭ ϭϬϵ͘Ϯ ϭϬϵ͘ϰ ϭϬϵ͘Ϭ ϭϬϵ͘ϯ ϭϬϵ͘ϭ ϭϬϴ͘Ϯ ϭϬϳ͘Ϭ ϭϬϲ͘ϯ ϭϬϱ͘ϳ ϭϬϱ͘ϭ ϭϬϰ͘ϱ ϭϬϰ͘ϯ ϭϬϯ͘ϱ ϭϬϯ͘Ϯ ϭϬϯ͘ϭ ϭϬϮ͘ϲ ϭϬϮ͘ϲ ϭϬϮ͘ϭ ϭϬϭ͘ϵ ϭϬϭ͘ϱ ϭϬϭ͘ϰ ϭϬϭ͘ϭ Ͳϯ͘ϴ Ϯ͘ϯ ϱ͘ϵ ϳ͘ϵ ϭϬ͘ϭ ϭϮ͘ϭ ϭϯ͘ϭ ϭϰ͘ϯ ϭϱ͘ϭ ϭϱ͘ϵ ϮϮ͘Ϭ Ϯϱ͘ϵ Ϯϴ͘Ϯ ϯϬ͘ϭ ϯϲ͘Ϯ ϯϲ͘ϰ ϯϲ͘Ϭ ϯϲ͘ϯ ϯϲ͘ϭ ϯϱ͘Ϯ ϯϰ͘Ϭ ϯϯ͘ϯ ϯϮ͘ϳ ϯϮ͘ϭ ϯϭ͘ϱ ϯϭ͘ϯ ϯϬ͘ϱ ϯϬ͘Ϯ ϯϬ͘ϭ Ϯϵ͘ϲ Ϯϵ͘ϲ Ϯϵ͘ϭ Ϯϴ͘ϵ Ϯϴ͘ϱ Ϯϴ͘ϰ Ϯϴ͘ϭ Ϯϳ͘ϴ Ϯϵ͘ϵ ϯϬ͘Ϭ Ϯϵ͘ϱ Ϯϵ͘ϴ ϯϬ͘Ϯ ϯϬ͘Ϭ ϯϬ͘Ϯ ϯϬ͘ϭ ϯϬ͘ϭ ϯϭ͘ϳ ϯϯ͘Ϯ ϯϯ͘ϰ ϯϯ͘ϴ ϰϮ͘ϯ ϰϭ͘Ϭ ϯϵ͘ϲ ϯϵ͘ϭ ϯϴ͘ϰ ϯϳ͘ϯ ϯϲ͘Ϭ ϯϱ͘ϯ ϯϰ͘ϴ ϯϰ͘ϰ ϯϰ͘Ϯ ϯϰ͘ϯ ϯϯ͘ϱ ϯϯ͘Ϯ ϯϮ͘ϵ ϯϮ͘ϰ ϯϮ͘ϲ ϯϮ͘ϳ ϯϯ͘ϯ ϯϯ͘ϱ ϯϯ͘ϴ ϯϯ͘ϱ Ϭ͘ϲ ϭ͘Ϭ ϭ͘Ϭ Ϭ͘ϵ ϭ͘Ϭ ϭ͘Ϭ ϭ͘Ϭ ϭ͘Ϭ ϭ͘Ϭ ϭ͘Ϭ ϭ͘ϱ Ϯ͘ϭ Ϯ͘Ϯ Ϯ͘ϰ ϭϲ͘ϵ ϭϮ͘ϳ ϵ͘Ϯ ϴ͘Ϯ ϳ͘Ϭ ϱ͘ϰ ϰ͘Ϭ ϯ͘ϰ ϯ͘Ϭ Ϯ͘ϴ Ϯ͘ϲ Ϯ͘ϳ Ϯ͘Ϯ Ϯ͘ϭ Ϯ͘Ϭ ϭ͘ϳ ϭ͘ϴ ϭ͘ϴ Ϯ͘ϭ Ϯ͘ϯ Ϯ͘ϰ Ϯ͘ϯ ϭ͘Ϭ ϭ͘Ϭ ϭ͘Ϭ ϭ͘Ϭ ϭ͘Ϭ ϭ͘Ϭ ϭ͘Ϭ ϭ͘Ϭ ϭ͘ϭ ϭ͘ϭ ϭ͘ϱ Ϯ͘Ϯ Ϯ͘ϱ ϯ͘ϱ Ϯϭ͘ϭ ϭϱ͘ϲ ϭϯ͘ϲ ϭϯ͘ϭ ϭϯ͘ϭ ϵ͘ϱ ϳ͘ϲ ϲ͘ϰ ϱ͘ϲ ϱ͘ϭ ϰ͘ϴ ϰ͘ϰ ϰ͘Ϭ ϯ͘ϵ ϯ͘ϵ ϰ͘Ϭ ϯ͘ϴ ϰ͘Ϭ ϰ͘ϭ ϰ͘ϭ ϯ͘ϵ ϯ͘ϵ ϭ͘Ϯ ϭ͘ϵ Ϯ͘Ϭ ϭ͘ϴ ϭ͘ϵ Ϯ͘ϭ Ϯ͘Ϭ Ϯ͘ϭ Ϯ͘Ϭ Ϯ͘Ϭ Ϯ͘ϵ ϰ͘ϰ ϱ͘ϳ ϳ͘ϱ ϰϰ͘ϱ ϯϳ͘Ϭ ϯϬ͘ϴ Ϯϵ͘ϰ Ϯϳ͘ϰ ϮϮ͘ϯ ϭϲ͘ϭ ϭϯ͘ϳ ϭϮ͘ϱ ϭϬ͘ϳ ϵ͘ϱ ϵ͘ϭ ϴ͘ϭ ϳ͘ϵ ϴ͘ϭ ϳ͘ϱ ϳ͘ϵ ϳ͘ϳ ϳ͘ϳ ϳ͘Ϯ ϳ͘Ϭ ϲ͘ϳ 3 Authorized licensed use limited to: Blue Origin LLC. Downloaded on January 22,2023 at 05:24:19 UTC from IEEE Xplore. Restrictions apply. L. Sudhakar received his Master Degree in Applied Electronics from Osmania University, Hyderabad. He joined STQC Directorate in 1987 and worked for 20 years involved in evaluation of commercial and telecom products as per International standards to comply with EMI/EMC and Safety requirements. He has conducted training programs in EMI/EMC Measurement and Design techniques to various industries. He has taken training in various international organizations like M/s Rohde and Schwarz, Germany, Siemens Plessey U.K. He is a Lead Auditor of ISO 9000/ISO 27000 Quality management systems. He has worked with TUV Rheinland, Japan for about 4 years in handling CE marking projects. Presently, working as Head, EMI/EMC lab in Astra Microwave Products Ltd, Hyderabad. Email: sudhakar.l@astramwp.com reverse power issues although it is not specified by the standard. By considering this factor, measurement was repeated using the 3dB, 100W attenuator. It is observed that the maximum forward power recorded with the addition of 3dB attenuator to achieve Curve #5 current is 44.5W at 1 MHz. CS114 testing is performed on the EUT while maintaining the calibrated forward power level as determined above or the maximum current level for the applicable limit, whichever is less stringent. Therefore in either case, pre-calibrated forward power is not exceeded. IV CONCLUSION Based on the comparison of theoretical and actual CS114 BCI calibration measurement it is observed that the required forward power level to generate the maximum current limit level (Curve #5) does not exceed 44.5W with 3dB pad. By applying [Criteria 1], the power required is 44.5*2 W which implicates RF amplifier of 100W is adequate for CS114 Calibration and Testing in the frequency range of 10 kHz to 200 MHz. It is therefore suggested to understand the importance of injection probes insertion loss characteristics as specified by the standard rather than preferring the high wattage amplifier. REFERENCES [1] MIL-STD-(³'HSDUWPHQWRI Defense Interface Standard, Requirements for the Control of Electromagnetic ,QWHUIHUHQFH &KDUDFWHULVWLFV RI 6XEV\VWHPV DQG (TXLSPHQW´ 20 August 1999. [2] MIL-STD-)³'HSDUWPHQWRI'HIHQVH,QWHUIDFH6WDQGDUG Requirements for the Control of Electromagnetic ,QWHUIHUHQFH &KDUDFWHULVWLFV RI 6XEV\VWHPV DQG (TXLSPHQW´ 10 December 2007. ACKNOWLEDGEMENT We would like to thank Director Technical and Director Operations, AMPL for their encouragement towards publishing this paper. $87+25¶6%,2-DATA W. Bilal Khan received his Diploma in Electronics and communication from Central Polytechnic College, Taramani and B.Tech from SRM University, Chennai. He joined EMC division, SAMEER - CEM, Chennai and was involved in evaluation of various electrical and electronic equipment as per civilian, Military and Automotive Standards from 2007-2012. Currently, he is working with Astra Microwave Products ltd., in EMI/EMC Testing of defense products. He has participated in conducting EMI/EMC seminars as a faculty member. He is a life member of the Society of EMC Engineers (India). Email: bilalkhan.w@astramwp.com 4 Authorized licensed use limited to: Blue Origin LLC. Downloaded on January 22,2023 at 05:24:19 UTC from IEEE Xplore. Restrictions apply.
