Design of coaxial aircell fixture for the measurement of electromagnetic properties

Seetha Rama Raju Vengala Raju


Coaxial aircells are designed and fabricated to measure the electromagnetic properties of ferrite materials in the frequency range from 1 MHz to 3.6 GHz. The S-parameters are measured connecting the aircell to a vector network analyzer (VNA). The electromagnetic properties such as complex permittivity and complex permeability are extracted using Nicolson-Ross-Weir (NRW) method and suitable air-gap corrections are made. For the optimization of the measured result and to estimate the error, the aircells are characterized in terms of their phase constant and resistivity of the aircell conductor. The measurements show that the electrical length is longer than the mechanical length of the aircell at all frequencies. The arithmetic mean of the resistivity of aircell of 7mm line size of length of 60 mm is about 66 nΩm. This paper presents a simple method whereby the phase constant and resistivity of the aircell can be determined accurately using transmission measurements made using a VNA.


Coaxial aircell, S-parameters, Complex permittivity, Complex permeability

Full Text:



D. K. Ghodgaonkar V. V. Varadan, V. K. Varadan, "A free-space method for measurement of dielectric constants and loss tangents at microwave frequencies,`` IEEE Trans. Instrum. Meas., vol. 38, pp. 789-793, 1989.

P. Skocik, P. Neumann, "Measurement of Complex Permittivity in Free Space,`` Procedia Eng., vol. 100, pp. 100-104, 2015.

F. C. Smith, B. Chambers, and J. C. Benett, "Methodology for accurate free-space characterization of radar absorbing materials,`` Proc. Inst. Elect. Eng. Sci. Meas. Technol., vol. 141, pp. 538-546, 1994.

M. J. Akhtar , L. Feher, M. Thumm, "Measurement of dielectric constant and loss tangent of epoxy resins using a waveguide approach,`` in Proc. IEEE Antennas Propag. Soc. Int. Symp., vol. 1, pp. 3179 – 3182, 2006.

H. Soleimania, Z. Abbasb, N. Yahyaa, H. Soleimanib, M. Yeganeh Ghotbic, "Determination of complex permittivity and permeability of lanthanum iron garnet filled PVDF-polymer composite using rectangular waveguide and Nicholson–Ross–Weir (NRW) method at X-band frequencies,`` Measurement., vol. 45, pp. 1621-1625, 2012.

B. Filali, F. Boone, J. Rhazi, G. Ballivy, "Design and Calibration of a Large Open-Ended Coaxial Probe for the Measurement of the Dielectric Properties of Concrete,`` IEEE Trans. Microw. Theory Tech., vol. 56, pp. 2322-2328, 2008.

D. M. Hagl, D. Popovic, S. C. Hagness, J. H. Booske, M. Okoniewski, "Sensing Volume of Open-Ended Coaxial Probes for Dielectric Characterization of Breast Tissue at Microwave Frequencies,`` IEEE Trans. Microw. Theory Tech., vol. 51, pp. 1194-1206, 2003.

J. Sheen, "Microwave Measurements of Dielectric Properties Using a Closed Cylindrical Cavity Dielectric Resonator,`` IEEE Trans. Dielectr. Electr. Insul., vol. 14, pp. 1139-1144, 2007.

J. Krupka, A. P. Gregory, O. C. Rochard, R. N. Clarke, B. Riddle, J. B. Jarvis, "Uncertainty of complex permittivity measurements by split-post dielectric resonator technique,`` J. Eur. Ceram. Soc., vol. 21, pp. 2673-2676, 2001.

V. Shemelin, N. Valles, "Improved accuracy of measurements of complex permittivity and permeability using transmission lines,`` Nucl. Instr. Meth. Phys. Res. A., vol. 767, pp. 385-396, 2014.

J. B. Jarvis, R. Geyer, P. Domich, "Improvements in transmission line permittivity and permeability measurements,`` in Precision Electromagnetic Measurements (CPEM) Conf. on Jun 1990, pp. 232-233.

J. Xu, M. Y. Koledintseva, Y. Zhang, Y. He, B. Matlin, R. E. DuBroff, J. L. Drewniak, J. Zhang, "Complex Permittivity and Permeability Measurements and Finite-Difference Time-Domain Simulation of Ferrite Materials,`` IEEE Trans. Electromagn. Compat., vol. 52, pp. 878-887, 2010.

B. O. Weinschel, "Air-filled coaxial lines as absolute impedance standards,`` Microw. J., vol. 7, pp. 47-50, 1964.

I. A. Harris, R. E. Spinney, "The realization of high-frequency impedance standards using air spaced coaxial lines,`` IEEE Trans. Instrum. Meas., vol. 13, pp. 265-272, 1964.

K. H. Wong, "Using precision coaxial air dielectric transmission lines as calibration and verification standards,`` Microw. J., vol. 31, pp. 83-92, 1998.

G. J. Kilby, N. M. Ridler, "Comparison of theoretical and measured values for attenuation of precision coaxial lines,`` Electron. Lett., vol. 28, pp. 1992-1994, 1992.

A. M. Nicolson and G. F. Ross, "Measurement of the intrinsic properties of materials by time-domain techniques,`` IEEE Trans. Instrum. Meas. vol. 19, pp. 377-382, 1970.

W. B. Weir, "Automatic measurement of complex dielectric constant and permeability at microwave frequencies,`` Proc. IEEE., vol. 62, pp. 33-36, 1974.

J. Baker-Jarvis, C. Jones, B. Riddle, M. Janezic, R. Geyer, J. Grosvenor and C. Weil, "Dielectric and magnetic measurements: A survey of nondestructive, quasinondestructive, and process- control techniques,`` Research in Nondestructive Evaluation, vol. 7, pp. 117-136, 1995.

J. Krupka, A. Abramowicz, "Measurements of Electromagnetic Properties of Materials at Microwave Frequencies``, XXXII International Conference of IMAPS - CPMT IEEE Poland Pułtusk 21 - 24 September 2008.

C. G. Koops, "On the Dispersion of Resistivity and Dielectric Constant of Some Semiconductors at Audio frequencies,`` Phys. Rev. Lett., vol. 83, pp. 121-124, 1951.

V. Seetha Rama Raju, "Effect of Ta2O5 addition on the electrical and magnetic properties of nanocrystalline MgCuZn ferrites,`` J. Mater. Res., vol. 29, pp. 2220-2228, 2014.

V. Seetha Rama Raju, "Complex permeability spectra of PbO and Ta2O5 added nanocrystalline MgCuZn ferrites,`` J. Magn. Magn. Mater., vol. 382, pp. 84-87, 2015.

T. Krishnaveni, B. Rajini Kanth, V. Seetha Rama Raju, S. R. Murthy, "Fabrication of multilayer chip inductors using Ni–Cu–Zn ferrites,`` J. Alloys Compd., vol. 414, pp. 282-286, 2006.

T. Slatineanua, A. R. Iordana, V. Oanceaa, M. N. Palamarua, I. Dumitrub, C. P. Constantinb, O. F. Caltun, "Magnetic and dielectric properties of Co–Zn ferrite,`` Mater. Sci. Eng. B., vol. 178, pp. 1040-1047, 2013.



© Copyright 2007-2016 JMOe Brazilian Microwave and Optoelectronics Society (SBMO) and Brazilian Society of Electromagnetism (SBMag)