Magnetic and Dielectric Properties of Composites Consisting of Oriented,Iron Flake Filler within a Thermoplastic Host: Part I. Material Fabrication and Electromagnetic Characterization

Abstract

Materials that contain both electric permittivity and magnetic permeability greater than unity (magneto-dielectrics) are currently being investigated for microwave applications. An experimental procedure for fabricating magneto-dielectric composite materials based upon flake-like iron inclusions was developed. Samples consisting of iron flakes oriented within a low loss thermoplastic host were produced by extrusion film forming, to minimize loss and maximize permeability. The electrical and magnetic properties of the magneto-dielectric samples were measured as a function of the filler’s aspect ratio, surface characteristics and volume fraction. It was found that forming iron powder into flakes increases the permeability by reducing the demagnetization factor of the shape of the particle. The change to higher aspect ratio filler also increased the dielectric constant and the dielectric loss due to greater instances of inter-particle conduction. Insulating the flakes with a low dielectric greatly significantly mitigated this effect.

Keywords

magneto-dielectric composite high-aspect ratio filler ferromagnetic flakes.

References

Pozar, D.M. ( 1992). Microstrip Antennas, Proceedings of the IEEE, 80(1): 79-91.

Carver, K. and J. Mink , (1981). Microstrip Antenna Technology. Antennas and Propagation , IEEE Transactions on [legacy, pre-1988], 29(1): 2-24.

Oliver, M.B. , Antar, Y.M.M. , Mongia, R.K. and Ittipiboon, A. ( 1994). Circularly-Polarized Dielectric Resonator Antenna, Electronics Letters, 30(17): 1361-1362.

Mongia, R.K. , Ittibipoon, A. and Cuhaci, M. ( 1994). Low Profile Dielectric Resonator Antennas Using a very High Permittivity Material, Electronics Letters, 30(17): 1362-1363.

James, J.R. , Schuler, A.J. and Binham, R.F. ( 1974). Reduction of Antenna Dimensions by Dielectric Loading , Electronics Letters, 10: 263-265.

Hwang, Y. , Zhang, Y.P. , Zheng, G.X. and Lo, T.K.C. ( 1995). Planar Inverted F Antenna Loaded with High Permittivity Material, Electronics Letters, 31(20): 1710-1712.

Colburn, J.S. and Rahmat-Samii, Y. (1999). Patch Antennas on Externally Perforated High Dielectric Constant Substrates, IEEE Transactions on Antennas and Propagation, 47(12): 1785-1794.

Chen, C.C. and Volakis, J.L. ( 2005). Bandwidth Broadening of Patch Antennas Using Nonuniform Substrates, Microwave and Optical Technology Letters, 47(5): 421-423.

Kiziltas, G. , Psychoudakis, D. , Volakis, J.L. and Kikuchi, N. ( 2003). Topology Design Optimization of Dielectric Substrates for Bandwidth Improvement of a Patch Antenna, IEEE Transactions on Antennas and Propagation, 51(10): 2732-2743.

10.

Rozanov, K.N. , Li, Z.W. , Chen, L.F. and Koledintseva , M.Y. (2005). Microwave Permeability of Co[sub 2]Z Composites, Journal of Applied Physics, 97(1): 013905-013907.

11.

Fiske, T.J. , Gokturk H.S. and Kalyon, D.M. (1997). Percolation in Magnetic Composites, Journal of Materials Science, 32(20): 5551-5560.

12.

Mosallaei, H. and Sarabandi, K. (2004). Magneto-dielectrics in Electromagnetics: Concept and Applications, IEEE Transactions on Antennas and Propagation, 52(6): 1558-1567.

13.

Mano, Y. and Bae, S. ( 2005). A Small Meander Antenna by Magneto-dielectric Material . Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications, MAPE 2005, IEEE International Symposium.

14.

Ermutlu, M.E. , Simovski, C.R. and Krkkinen, M.K. (2005). Miniaturization of Patch Antennas with New Artificial Magnetic Layers. Antenna Technology: Small Antennas and Novel Metamaterials, IWAT 2005 IEEE International Workshop, pp. 87-90.

15.

Mirza, I.O. , Shi, S. , Fazi, C. , Mait, J.N. and Prather, D.W. ( 2007). A Study of Loop Antenna Miniaturization using Split Ring Resonators. In: Antennas and Propagation Society International Symposium, 2007 IEEE, pp. 1865-1868.

16.

Ikonen, P.M.T. , Maslovski, S.I. , Simovski, C.R. and Tretyakov , S.A. (2006). On Artificial Magneto-Dielectric Loading for Improving the Impedance Bandwidth Properties of Microstrip Antennas. IEEE Transactions on Antennas and Propagation, 54(6): pp. 1654-1662.

17.

Ikonen, P. , Maslovski, S. and Tretyakov, S. ( 2005). PIFA Loaded with Artificial Magnetic Material: Practical Example for Two Utilization Strategies, Microwave and Optical Technology Letters, 46(3): 205-210.

18.

Karkkainen, M. and Ikonen, P. (2005). Patch Antenna with Stacked Split-ring Resonators as Artificial Magneto-dielectric Substrate, Microwave and Optical Technology Letters, 46(6): 554-556.

19.

Hansen, R.C. and Burke, M. (2000). Antennas with Magneto-dielectrics . Microwave and Optical Technology Letters, 26(2): 75-78.

20.

Zhao, Y. , Ni, C. , David, K. , Zhang, X. and Xiao, J.Q. ( 2004). Exchange-coupled Soft Magnetic FeNi-SiO2 Nanocomposite . Journal of Physical Chemistry B, 108(12): 3691-3693.

21.

Stober, W. , Fink, A. and Bohn, E. ( 1968). Controlled Growth of Monodisperse Silica Spheres in Micron Size Range. Journal of Colloid and Interface Science, 26(1): 62-69.

22.

Yin, Y.D. et al. (2002). Silver Nanowires can be Directly Coated with Amorphous Silica to Generate Well-controlled Coaxial Nanocables of Silver/Silica, Nano Letters, 2(4): 427-430.

23.

Zhao, Y.W. , Zhang, X.K. and Xiao, J.Q. ( 2005). Submicrometer Laminated Fe/SiO2 Soft Magnetic Composites-an Effective Route to Materials for High-frequency Applications. Advanced Materials, 17(7): 915-918.

24.

McCullough, R.L. (1985). Generalized Combining Rules for Predicting Transport-Properties of Composite-Materials. Composites Science and Technology, 22(1): 3-21.