雷達吸波材料又稱微波吸收材料，具有特殊的電磁特性能將入射電磁波能量吸收並轉化成熱能消散掉，目前主要應用於軍事與民生兩大領域上。雷達吸波體可分為結構型與塗覆型兩類；就吸波特型可分為介電吸收與磁吸收型兩類。吸波材料的吸波機制主要由材料複數介電係數、複數導磁率、塗層厚度及目標頻率所控制，將六組參數匹配後能達到最佳吸波效能。本研究利用阻抗匹配概念繪製出適用於介電吸收型材料的阻抗匹配圖，以利於日後設計介電損耗型吸波體時，提供快速的設計依據。
本研究推導出共振腔微擾法於計算複數導磁率的解析解公式，利用推導出公式的計算結果與ANSYS HFSS高頻模擬分析軟體的數值模擬結果相比，顯示兩者的複導磁率實部差異約在5%以下、複導磁率虛部差異約在6%以下。確認公式的準確性後，利用羰基鐵粉混合環氧樹脂製備傳輸反射法及共振腔微擾法測試試片，將兩種方法測量結果相比可得複數導磁率實部及虛部差異分別約3.8%~10%及2.9%~10.3%。在使用共振腔微擾法測量材料電磁特性時，試片長度需貫穿腔體才能準確量測，當測試粉末製作困難或成本太高而造成試片長度無法貫穿腔體，會造成測量上的誤差，文獻上未曾探討試片長度造成的誤差如何修正。本研究採用1971年Buranov等人所推導的共振腔微擾法複數介電係數公式來計算小試片的複數介電係數，利用ANSYS HFSS做數值模擬，結果顯示數值模擬部分，複數介電係數實部誤差從33.7%下降至7.8%；複數介電係數虛部誤差從40.0%下降至2.0%。實驗部分，本研究將羰基鐵粉末混合環氧樹脂製備量測試片，並將試片切割成長度4 mm、6 mm、8 mm及10 mm，直徑1 mm的試片實際量測。測量結果顯示，複數介電係數實部及虛部誤差分別從52.3%降低至1.5%及82.2%降低至6.8%。
本研究以不同寬厚比的二氧化錳為介電性吸波材料，以不同寬厚比的羰基鐵粉、奈米鐵線、高導磁鐵粉及鐵鎳鉬坡莫合金為磁性吸波材料混合環氧樹脂製備吸波複合材料。利用網路分析儀搭配同軸波導管及X-Band矩形共振腔進行材料電磁特性量測，並探討不同重量百分比、寬厚比與塗層厚度對吸波效能的影響。研究結果顯示吸收劑形狀對吸波效能有重大的影響，在S-band與H-band頻段，因片狀吸收劑可降低渦電流損耗及提高空間電荷極化，在電磁特性上優於球狀吸收劑，故於相同厚度下，片狀吸收劑吸波效能較針狀及球狀吸收劑容易達到目標。在特定頻率下，片狀吸收劑可提供較薄的塗層厚度。針狀吸波劑提供較高的長徑比及形狀上的非等向性，使電磁特性較球狀吸收劑高，吸波效能也較優異。

In this thesis, investigations have been made on microwave characteristics of composite absorbers containing high-aspect-ratio dielectric and magnetic fillers. We propose two analytical resonant cavity perturbation formulae for the complex permeability of electromagnetic materials, and its accuracy is confirmed by numerical results of finite element method and the experimental data from the waveguide transmission/reflection method. The proposed formula is especially useful for the electromagnetic characterization of magnetic particles and magnetic thin films with limited quantities.
The complex permittivity and permeability of composite samples prepared by mixing MnO2 nanoparticles, MnO2 nanorods, iron powder, carbonyl iron powder and FeNiMo alloy powder individually with epoxy resin were measured and determined by using the transmission/reflection method, whereas those of surface-modified iron nanowire/epoxy composite were measured by the resonant cavity perturbation method. Based on these measured quantities, the reflection loss of microwave abosrber can be predicted by using the transmission line theory. Absorption properties of microwave absorbers backed by perfect conductors can be calculated from the measured complex permittivity, complex permeability, target frequency and the coating layer thickness. The minimum reflection loss occurring at the matching frequency is found to move toward the lower frequency region with increasing real part of permittivity, real and imaginary parts of permeability of the fillers.
Experiment results of this study show that the particle shape of fillers strongly influences the absorption properties of the microwave composite absorbers. For the same thickness of absorbers, flake-shaped particles achieve higher microwave absorption. For the same concentration of fillers, flake-shaped particles provide higher permittivity and permeability due to their high aspect-ratios in S-band and H-band than the corresponding ones of rod-shaped and sphere-shaped particles. Compared with spherical particles, rod-shaped particles exhibit higher shape anisotropy, larger aspect ratio, superior electromagnetic properties, and better absorption properties in the high frequency range.

[1] Vinoy, K. J., and Jha, R. M., 1996, Radar Absorbing Materials, USA: Kluwer Academic.
[2] Knott, E. F., Shaeffer, J. F., and Tuley, M. T., 1993, Radar Cross Section, London: Artech House.
[3] Wu, L. Z., Ding, J., Jiang, H. B., Neo, C. P., Chen, L. F., and Ong, C. K., 2006, “High Frequency Complex Permeability of Iron Particles in a Nonmagnetic Matrix,” Journal of Applied Physics, 99, pp. 083905.
[4] Walser, R. M., Win, W., and Valanju,P. M., 1998, “Shape-Optimized Ferromagnetic Particles with Maximum Theoretical Microwave Susceptibility,” IEEE Transactions on Magnetics., 34, pp. 1390−1392.
[5] Ma, F., Qin, Y., and Li, Y. Z., 2010, “Enhanced Microwave Performance of Cobalt Nanoflakes with Strong Shape Anisotropy,” Applied Physics Letters, 96, pp. 202507.
[6] Fante, R. L., McCormack, M. T., 1988, “Reflection Properties of the Salisbury Screen,” IEEE Trans. Antennas and Propagation, 36, pp. 1443−1454.
[7] Du Toit, L. J., 1994, “The Design of Jauman Absorbers,” IEEE Antennas and Propagation Magazine, 36, pp. 17−25.
[8] Severin, H., 1956, “Nonreflecting Absorbers for Microwave Radiation,” IRE Transactions on Antennas and Propagation, 4, pp. 385-392.
[9] Wang, M. J., Gray, C. A., Reznek, S. R., Mahmud, K., and Kutsovsky, Y., 2003, “ Carbon Black,” Encyclopedia of Chemical Technology, 4, pp. 761-803.
[10] Emerson, W., 1973, “Electromagnetic Wave Absorbers and Anechoic Chambers through the Years,” IEEE Transaction on Antennas and Propagation, 21, pp.484-490.
[11] Kwon, S. K., Ahn, J. M., Kim, G. H., Chun, C. H., Lee, J. H., and Hwang, J. S., 2002, “Microwave Absorbing Properties of Carbon Black/Silicone Rubber Blend,” Polymer Engineering and Science, 42, pp. 2165-2171.
[12] Kim, J. B., Lee, S. K., and Kim, C. G., 2008, “Comparison Study on the Effect of Carbon Nano Materials for Single-Layer Microwave Absorbers in X-Band,” Composites Science and Technology, 68, pp. 2909−2916.
[13] Wang, X. P., Wang, L. J., Liu, X. F., Yang, C., Jing, L. W., Pan, X. F., and Li, S. K., 2013, “The Synthesis of Vertically Oriented Carbon Nanosheet-Carbon Nanotube Hybrid Films and Their Excellent Field Emission Properties,” Carbon, 58, pp. 170-174.
[14] Anwar, H., George, A. E., and Hill, I. G., 2013, “Vertically-Aligned Carbon Nanotube Counter Electrodes for Dye-Sensitized Solar Cells,” Solar Energy, 88, pp. 129-136.
[15] D’Souza, O. J., Mascarenhas, R. J., Thomas, T., Namboothiri, I. N., Ragamathi, M., Martis, P., and Dalhalle, J., 2013, “Electrochemical Determination of L-Tryptophan Based on a Multiwall Carbon Nanotube/Mg-Al Layered Double Hydroxide Modified Carbon Paste Electrode as a Sensor,” Journal of Electroanalytical Chemistry, 704, pp. 220-226.
[16] Singh, A. P., Gupta, B. K., Mishra, M., Chandra, A., Mathur, R. B., and Dhawan, S. K., 2013, “Multiwalled Carbon Nanotube/Cement Composites with Exceptional Electromagnentic Interference Shielding Prpoerties,” Carbon, 56, pp. 86-96.
[17] Fan, Z., Luo, G., Zhang, Z., Zhou, L., and Wei, F., 2006, “Electromagnetic and Microwave Absorbing Properties of Multi-walled Carbon Nanotubes/Polymer Composites,” Materials Science and Engineering: B, 132, pp. 85-89.
[18] Ting, T. H., Chiang, C. C., Lin, P. C., and Lin, C. H., 2013, “Optimisation of the Electromagnetic Matching of Manganese Dioxide/Multi-Wall Carbon Nanotube Composites as Dielectric Microwave-Absorbing Materials,” Journal of Magnetism and Magnetic Materials, 339, pp. 100-105.
[19] Lv, R., Kang, F., Gu, J., Gui, X., Wei, J., Wang, K., and Wu, D., 2008, “Carbon Nanotubes Filled with Ferromagnetic Alloy Nanowires: Lightweight and Wide-Band Microwave Absorber,” Applied Physics Letters, 93, 223105.
[20] Zhao, D. L., and Shen, X. L., 2008, “Microwave Absorbing Property and Complex Permittivity and Permeability of Epoxy Composites Containing Ni-Coated and Ag Filled Carbon Nanotubes,” Composites Science and Technology, 68, pp. 2902-2908.
[21] Ugarte, D., 1995, “Onion-Like Graphitic Particles,” Carbon, 33, pp. 989-993.
[22] Chhowalla, M., Wang, H., Sano, N., Teo, K. B. K., and Lee, S. B., and Amaratunga, G. A. J., 2003, “Carbon Onions: Carriers of the 217.5 nm Interstellar Absorption Feature,” Physical Review Letters, 90, pp.155501-155504.
[23] Hirata, A., Ugarashi, M., and Kaito, T., 2004, “Study on Solid Lubricant Properties of Carbon Onions Produced by Heat Treatment of Diamond Clusters or Particles,” Tribology International, 37, pp. 899-905.
[24] Liu, X., Or, S. W., Jin, C., Lv, Y., Li, W., Feng, C., Xiao, F., and Sun, Y., 2013, “Co3O4/C Nanocapsules with Onion-Like Carbon Shells as Anode Material for Lithium Ion Batteries,” Electrochimica Acta, 100, pp. 140-146.
[25] Novoselov, K. S., Geim, A. K., Morozov, S. V., Jiang, D., Zhang, Y., Dubonos, S. V., Grigorieva, I. V., and Firsov, A. A., 2004, “Electric Field Effect in Atomically Thin Carbon Films,” Science, 306, pp. 666-669.
[26] Zhu, Y., Murali, S., Stoller, M. D., Velamakanni, A., Piner, R. D., and Ruoff, R. S., 2010, “Microwave Assisted Exfoliation and Reduction of Graphite Oxide for Ultracapacitors,” Carbon, 48, pp. 2118-2122.
[27] Blake, P., Brimicombe, P. D., Nair, R. R., Booth, T. J., Jiang, D., Schedin, F., Ponomarenko, L. A., Morozov, S. V., Gleeson, H. F., Hill, E. W., Geim, A. K., and Novoselov, K. S., 2008, “Graphene-Based Liquid Crystal Device,” Nano Letters, 8, pp. 1704-1708.
[28] Stankovich, S., Dikin, D. A., Dommett, G. H. B., Kohlhaas, K. M., Zimney, E. J., Stach, E. A., Piner, R. D., Nguyen, S. T., and Ruoff, R. S., 2006, “Graphene-Based Composite Materials,” Nature, 442, pp. 282-286.
[29] Liang, J., Wang, Y., Huang, Y., Ma, Y., Liu, Z., Cai, J., Zhang, C., Gao, H., and Chen, Y., 2009, “Electromagnetic Interference Shielding of Graphene/Epoxy Composites,” Carbon, 47, 922-925.
[30] Wang, C., Han, X., Xu, P., Zhang, X., Du, Y., Hu, S., Wang, J., and Wang, X., 2011, “The Electromagnetic Property of Chemically Reduced Graphene Oxide and Its Application as Microwave Absorbing Material,” Applied Physics Letters, 98, pp. 072906.
[31] Fu, M., Jiao, Q., and Zhao, Y., 2013, “Preparation of NiFe2O4 Nanorod-Graphene Composites Via an Ionic Liquid Assisted One-Step Hydrothermal Approach and Their Microwave Absorbing Properties,” Journal of Materials Chemistry A, 18, pp. 5577-5586.
[32] Reddy, R. N., and Reddy, R. G., 2004, “Synthesis and Electrochemical Characterization of Amorphous MnO2 Electrichemical Capacitor Electrode Material,” Journal of Powder Source, 132, 315-320.
[33] Chen, Y., Liu, C., Li, F., Cheng, H. M., 2005, “Preparation of Single-Crystal α-MnO2 Nanorods and Nanoneedles from Aqueous Solution,” Journal of Alloys and Compounds, 397, pp. 282-285.
[34] Toupin, M., Brousse, T., and Belanger, D., 2004, “Charge Storage Mechanism of MnO2 Electrode Used in Aqueous Electrochemical Capacitor,” Chemistry of Materials, 16, pp. 3184-3190.
[35] Xia, H., Feng, J., Wang, H., Lai, M. O., and Lu, L., 2010, “MnO2 Nanotube and Nanowire Arrays by Electrochemical Deposition for Supercapacitors,” Journal of Powder Source, 195, pp. 4410-4413.
[36] Ammundsen, B., and Jens, P., 2001, “Novel Lithium-Ion Cathode Materials Based on Layered Manganese Oxides,” Advanced Materials, 12, pp. 943-956.
[37] Jia, Z., Duan, Y., Li, S., Li, X., and Liu, S., 2010, “The Effects of High Magnetic Field on the Morphology and Microwave Electromagnetic Properties of MnO2 Powder,” Journal of Solid State Chemistry, 183, pp.1490-1495.
[38] Li, Y., Yao, X., Wang, X., and Zhang, L., 2010, “Studies of Resistivity and Dielectric Properties of Manganese-Doped Barium Titanate Sintered in Pure Nitrogen,” Ferroelectrics, 384, pp. 73-78.
[39] Suchanicz, j., Smeltere, I., Finder, A., Konieczny, K., Garbarz-Glos, B., Rujakiewicz-Koronska, R., Latas, M., Antonova, M., Sternberg, A., and Sokolowski, M., 2011, “Dielectric and Ferroelectric Properties of Lead-Free NKN and NKN-Based Creamics,” Ferroelectric, 424, pp.53-58.
[40] Wang, X., Ni, S., Zhou, G., Sun, X., Yang, F., Wang, J., and He, D., 2010, “Facile Synthesis of Ultra-Long α-MnO2 Nanowires and Their Microwave Absorption Properties,” Materials Letters, 64, pp. 1496-1498.
[41] Hu, J., Duan, Y., Zhang, J., Jing, H., Liu, S., and Li, W., 2011, “γ-MnO2/Polyaniline Composites: Preparation, Characterization and Applications in Microwave Absorption,” Physica B, 406, pp. 1950-1955.
[42] Liang, W. F., Yang, R. B., and Choi, S. T., 2012, “Microwave Complex Permittivity and Absorption of MnO2 Nanorods and Nanoparticles,” Ferroelectrics, 434, pp. 100-106.
[43] Wang, J., He, Y., He, Peng, and Zhou, B., 2008, “Sintered Cu Alloyed Stainless Steels and Their Corrosion Behavior,” Journal of Materials Engineering and Performance, 17, pp. 780-784.
[44] Yang, R. B., and Liang W. F., 2011, “Microwave Properties of High-Aspect- Ratio Carbonyl Iron/Epoxy Absorber,” Journal of Applied Physics, 109, pp. 07A311.
[45] Qing, Y., Zhou, W., Luo, Fa., and Zhu, D., 2009, “Microwave-Absorbing and Mechanical Properties of Carbonyl-Iron/Epoxy-Silicone Resin Coatings,” Journal of Magnetism and Magnetic Materials, 321, pp. 25-28.
[46] Wang, M., Duan, Y., Liu, S., Li, X., and Ji, Z., 2009, “Absorption properties of carbonyl-iron/carbon black double-layer microwave absorbers,” Journal of Magnetism and Magnetic Materials, vol. 321, pp. 3442.
[47] Meshram, M. R., Agrawal, N. K., Sinha, B., and Misra, P. S., 2004, “Characterization of M-Type Barium Hexagonal Ferrite-Based Wide Band Microwave Absorber,” Journal of Magnetism and Magnetic Materials, 271, pp. 207-214.
[48] Hwang, Y., 2006, “Microwave Absorbing Properties of NiZn-Ferrite Synthesized from Waste Iron Oxide Catalyst,” Materials Letters, 60, pp. 3277-3280.
[49] Zhao, D. L., Lv, Q., and Shen, Z. M., 2009, “Fabrication and Microwave Absorbing Properties of Ni-Zn Spinel Ferrites,” Journal of Alloys and Compounds, 480, pp. 634-638.
[50] Shaikh, P. A., Kambale, R. C., Rao, A. V., and Kolekar, Y. D., 2010, “Structural, Magnetic and Electrical Properties of Co-Ni-Mn Ferrites Synthesized by Co-precipitation Method,” Journal of Alloys and Compounds, 492, pp. 590-596.
[51] Ruan, S. P., Xu, B. K., Suo, H., Wu, F. Q., Xiang, S. Q., and Zhao, M. Y., 2000, “Microwave Absorptive Behavior of ZnCo-Substituted W-Type Ba Hexaferrite Nanocrystalline Composite Material,” Journal of Magnetism and Magnetic Materials, 212, pp. 175-177.
[52] Ichiyanagi, Y., Uehashi, T., and Yamada, S., 2004, “Magnetic Properties of Ni-Zn Ferrite Nanoparticles,” Physica Status Solidi (C), 12, pp. 3485-3488.
[53] Li, L., Chen, K., Liu, H., Tong, G., Qian, H., and Hao, B., 2013, “Attractive Microwave-Absorbing Properties of M-BaFe12O19 Ferrite,” Journal of Alloys and Compounds, 557, pp. 11-17.
[54] Yang, R. B., Liang, W. F., and Lin, C. K., 2011, “Electromagnetic Characteristics of Manganese Oxide-Coated Fe3O4 Nanoparticles at 2-18 GHz,” Journal of Applied Physics, 109, pp. 07D722.
[55] Yang, R. B., Liang, W. F., Chang, C. C., Lin, C. K., Liu, S. T., and Kuo, K. M., 2012, “Complex Dielectric Permittivity and Magnetic Permeability of Fe/Fe3O4 Composite Particles in 2-18 GHz,” Ferroelectrics, 434, pp. 77-82.
[56] Xu, H. L., Shen, Y., Bi, H., Liang, W. F., and Yang, R. B., 2012, “Preparation and Microwave Absorption Properties of Fe3O4 Hollow Microspheres,” Ferroelectrics, 435, pp. 98-103.
[57] Kim, S. S., Kim, S. T., Yoon, Y. C., and Lee, K S., 2005, “Magnetic, Dielectric, and Microwave Absorbing Properties of Iron Particles Dispersed in Rubber Matrix in Gigahertz Frequencies,” Journal of Applied Physics, 97, pp. 07D722.
[58] Sun, J., Xu, H. L., Shen, Y., Bi, H., Liang, W. F., and Yang, R. B., 2013, “Enhanced microwave absorption properties of the milled flake-shaped FeSiAl/graphite composites,” Journal of Alloys and Compounds, 548, pp. 18-22.
[59] Liu, X. G., Qu, Z. Q., Geng, D. Y., Han, Z., Wang, H., Li, B., Bruck, E., and Zhang, Z. D., 2010, “Enhanced Absorption Bandwidth in Carbon-Coated Supermalloy FeNiMo Nanocapsules for a Thin Absorb Thickness,” Journal of Alloys and Compounds, 506, pp. 826-830.
[60] Yang, R. B., and Liang, W. F., 2013, “Microwave Absorbing Characteristics of Flake-Shaped FeNiMo/epoxy Composites,” Journal of Applied Physics, 113, pp. 17A315.
[61] Shen, L. C., Marouni, H., Zhang, Y. X., and Shi, X. D., 1987, “Analysis of the Parallel-Disk Sample Holder for Dielectric Permittivity Measurement,” IEEE Transactions on Geoscience and Remote Sensing, GE-25, pp. 534-540.
[62] Buck, N. L., 1996, “Calibration of Dielectric Constant Probes Using Salt Solutions of Unknown Conductivity,” IEEE Transactions on Instrumentation and Measurement, 45, pp. 84-88.
[63] Darayan, S., Liu, C., Shen, L. C., and Shattuck, D., 1998, “Measurement of Electrical Properties of Contaminated Soil,” Geophysical Prospecting, 46, pp. 477-488.
[64] Baker-Jarvis, J., Vanzura, E. J., and Kissick, W. A., 1990, “Improved Technique for Determining Complex Permittivity with the Transmission/Reflection Method,” IEEE Transactions on Microwave Theory and Techniques, 38, pp.1096-1103.
[65] Hajian, M., Mathew, K .T., and Ligthart, L. P., 1999, “Measurements of Complex Permittivity with Waveguide Resonator Using Perturbation Technique,” Microwave and Optical Technology Letters, 21, pp. 269-272.
[66] Folgero, K., and Tjomsland, T., 1996, “Permittivity Measurement of Thin Liquid Layers Using Open-Ended Coaxial Probes,” Measurement Science and Technology, 7, pp. 1164-1173.
[67] Belhadj-tahar, N. E., Fourrier-lamer, A., and Chanterac, H. D., 1990, “Broad-Band Simultaneous Measurement of Complex Permittivity and Permeability Using a Coaxial Discontinuity,” IEEE Transactions on Microwave Theory and Techniques, 38, pp. 1-7.
[68] Boughriet, A. H., Legrand, C., and Chapoton, A., 1997, “Noniterative Stable Transmission/Reflection Method for Low-Loss Material Complex Permittivity Determination,” IEEE Transactions on Microwave Theory and Techniques, 45, pp. 52-57.
[69] Varadan, V. V., Hollinger, R. D., Ghodgaonkar, D. K., and Varadan, V. K., 1991, “Free-Space, Broadband Measurements of High-Temperature, Complex Dielectric Properties at Microwave Frequencies,” IEEE Transactions on Microwave Theory and Techniques, 40, pp. 842-846.
[70] Li, S., Akyel, C., and Bosisio, R. G., 1981, “Precise Calculations and Measurements on the Complex Dielectric Constant of Lossy Materials Using TM010 Cavity Perturbation Techniques,” IEEE Transactions on Microwave Theory and Techniques, MTT-29, pp. 1041-1048.
[71] Dube, D. C., Lanagan, M. T., Kim, J. H., and Jang, S. J., 1988, “Dielectric Measurements on Substrate Materials at Microwave Frequencies Using a Cavity Perturbation Technique,” Journal of Applied Physics, 63, pp. 2466.
[72] Yang, R. B., Liang, W. F., Lin, W. S., Lin, H. M., Tsay, C. Y., and Lin, C. K., 2011, “Microwave Absorbing Properties of Iron Nanowire at X-Band Frequencies,” Journal of Applied Physics, 109, pp. 07527.
[73] Buranov, L. I., and Shchegolev, I. F., 1971, “Method of Measuring the Conductivity of Small Crystals at a Frequency of 1010 Hz,” Instruments and Experimental Techniques, 2, pp. 171.
[74] Guru, B. S., and Hiziroglu, H. R., 2004, Electromagnetic Field Theory Fundamentals, Cambridge University Press.
[75] Pozar, D. M., 2009, Microwave Engineering, John Wiley and Sons, Inc.
[76] Musal, H. M., and Hahn, H. T., 1989, “Thin-Layer Electromagnetic Absorber Design,” IEEE Transactions on Magnetics, 25, pp. 3851-3853.
[77] Kittel, C., 1996, Introduction to Solid State Physics, New York: Wiley.
[78] Osborn, J. A., 1945, “Demagnetizing Factors of the General Ellipsoid,” Physical Review, 67, pp. 351-357.
[79] Nicolson, A. M., and Ross, G. F., 1970, “Measurement of the Intrinsic Properties of Materials by Time-Domain Techniques,” IEEE Transactions on Instrumentation and Measurement, 19, pp. 377-382.
[80] Suryanarayana, C., 2001, “Mechanical alloying and milling,” Progress in Materials Science, 46, pp. 1.
[81] Wang, X., Gong, R., Li, X., He, Y., Liu, L., and Li, P., 2007, “Preparation and Electromagnetic Characteristics of Silica Coated Fe-Ni-Mo Alloy Flakes,” Journal of Materials Science: Materials in Electronics, 18, pp. 481-486.
[82] Kasagi, T., Tsutaoka, T., and Hatakeyama, K., 2006, “Negative Permeability Spectra in Permalloy Granular Composite Materials,” Applied Physics Letters, 88, pp. 172502.