2016 International Conference on Radar, Antenna, Microwave, Electronics, and Telecommunications
Measurement of Complex Permittivity and Permeability ofHexagonal Ferrite Composite Material U sing a Waveguide in Microwave Band
Erfan Handoko, Mangasi A.M., and Iwan S.
Department of Physics Universitas Negeri Jakarta
Jakarta, Tndonesia [email protected]
Maulana Randa Balitbang
Kementerian Pertahanan Rl
Jakarta, Tndonesia
Mudrik Alaydrus
Department of Electrical Engineering Universitas Mercu Buana
Jakarta, Tndonesia
Abstract-This paper reports a method for measuring for the complex permittivity and permeability of hexagonal ferrite composite as lossy material. The measurement using a waveguide in the microwave band. In order to measure the S-parameter of hexagonal ferrite, a sam pIe should completely fill in the waveguide end and the sampIe holder. The complex permittivity and permeability of the hexagonal ferrite composite material are measured using the vector network analyzer (VNA) in the frequency range from 7 to 14 GHz. Their complex permeability and permittivity, magnetic and dielectric loss tangent va lues were calculated at given thickness according to NRW formula and transmit line method in microwave frequency. The proposed measurement method can be a useful technique for measuring dielectric and magnetic properties of absorbing materials
K�words-Hexagonal ferrite composite; complex permittivity and permeability; waveguide; NRW and transmit line method
1. INTRODUCTION
Due to the usefulness of microwave absorbing materials for telecommunication systems and military systems, research on radar absorbing material (RAM) attracts considerable attention in many countries [1,2]. The measurement of the complex permittivity and permeability in solid materials, the S-parameter method employing a waveguide line is applied [3]. Various methods for the measurement of the complex permittivity and permeability of the solid materials have been reported [4,5]. Few results of the measurement of their composition of hexagonal ferrite have been reported for determination of the complex permittivity and permeability in X-band frequencies [6-9].
In this paper, a hexagonal ferrite composite material with a thickness dis placed in a rectangular waveguide. With a vector network analyzer, we measure the reflection S 11 and transmission factor S21 of the structure in the microwave band 7 -14 GHz. Based on these measurement, the complex
permittivity and permeability of hexagonal ferrite composite material are determined by Nicolson-Ross-Weir (NRW) method.
TI. EXPERIMENTAL METHOD
Hexagonal ferrite, BaFeIOCoO.8Tio.8MnoA019 was synthesized from stoichiometric mixtures of BaC03, Fe203, C0304,Ti02 and MnC03 by ceramic method and crushed for 1 h and sintered at 1100 °C for 5 h. The composite material was prepared by mixing ferrite with epoxy resin The sampie was characterized at room temperature using vector network analyzer (VNA) Rohde-Schwarz ZVLl3 to measure the reflected signal (S 11) and transmitted signal (S21) for 7-14 GHz frequencies.S 11 and S21 parameters from measurement are used to calculate the complex permittivity, permeability and tangent loss
TTT. RESUL TS AND DISCUSSION
A. Sampie Preparation and Transmission Line Method Fig. 1 shows transmission line methods involve placing hexagonal ferrite material inside a portion of an enclosed transmission line. The transmission line used here is a section of rectangular waveguide for X-Band Applications. The complexrelative permittivity (Er) and permeability (!lr) are then calculated for given thickness according to Nicolson-Ross
Weir (NRW) method [IO]from the measurement of the reflected signal (S 11) and transmitted signal (S21).
Hexagonal ferrite composite with sampie holder (Fig. 1) is placed in a waveguide with width 22.86 mm, height 10.16 mm and thickness 2 mm. The complex-valued S-parameters are obtained by a vector network analyzer measurement (Fig. 2).
The NR W method is then formulated using the following steps.
978-1-5090-6100-6116/$31.00 ©2016 IEEE 28
Port 1
Reflection signal (SIl)
Port 2
T ranslllis s ion signal (S21)
Fig. I. Sampie holder and transmission line methods for hexagonal ferrite.
Firstly, for simplification we used the following number,
K = (511)2_(521)2+1 2(511)
Then, the reflection coefficient ( r) is then given by r= K±VK2 -1, Ir!::; 1,
and the transmission coefficient (T) is given by equation T = (511)+(521)+r 1-(511+521)1
(1)
(2)
(3)
Finally the complex relative permeability and permitlivity of hexagonal ferrite can be formulated by
1+ /
fl = A(l-Tl ---
JRi1
Aa Ai'c = A� /1
(
AC 12_ [
_1 Zn 2nd(
.!:.T)]
2)
(4)
(5)
where Ao and Ac are the free space and the cutoff wavelength and with
...!:... =
(_ [
_1 Zn(
.!:.)]
2)
/12 2nd T (6)
By equating the equation (4) and (5), The relative complex permeability can be determined and hence thecomplex relative permittivity value.
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The magnetic and electricloss tangent of a materialis defmed as
and
tanöe=7' r!'
(7)
(8)
the greater the loss tangent of the material, the greater the atlenuation as the wave travelsthrough the material.
B. S-Parameter Measurement
Fig. 2 shows the measurement resuIts of s paramaters at frequencies ranging from 7 to 14 GHz. S 11 is intensities level as a function of frequency. The resuIts confirm that in the range 7 to 14 GHz, barium hexaferrite absorb the wave which have various reflection intensity. lts suggested from the reflection factor (S 11) which has value between -10 dB to -15 dB. Further results show there is no transmission detected in the range of frequencies 7 up to 14 GHz. lt can be understood from the transmission intensity which has value ranging from - 20 to -25 GHz.
C. Magnetic and Dielectric Properties
With the measured S-parameters, the complex relative permeability and permitlivity can be calculated by eq. (4) and (5). Fig. 3 shows the resuIts. As we can see, the real part of the relative permeability changes significantly from about 60 at lower frequencies to about 5 at higher frequencies. We see also radical changes in imaginary part of the relative permeability. Which means, the magnetic losses are smaller at higher frequencies than at lower frequencies.
The real part of the relative permittivity, as given in Fig.3, changes from about 7 at lower frequencies to about 3 at higher frequencies, whereas its imaginary part increases from lower frequency, then decreases again at higher frequencies.
0 0
-5
-10 -2
-15 -4
m (f)
� -20 I\)
� -6 c:
� -25 E!
(f)
-30
-8 -35
Frequency (GHz)
Fig. 2. Results of measurement of the S-parameter of hexagonal ferrite.
.� 15 CI]
Q)
E Q) CL
'0 t:
CI] Cl.
ro Q)
a:::
100 90 80
70
60
50 40 30 20
10
24 22 20
0
� 16 .>
:E 1 6 E 14
CL 12 Q)
�
10� 6
� 6
a::: 4
2
\
\
7 8
100 90 80 �
70 15 <1l Q) 60 E
CL Q;
50 '0
40 1::
" <1l
f.l a.
�--"'---"'-.. --- 30 �
---
<1l 20 .� Ol
<1l
§
9 10 11 12 13
Frequency (GHz)
c: ,
14
10 0
24 22 20 � 18
:�
16 'E
14
�
-12 0
10 � 1::
8 �
<1l
6 c
4 '0, <1l
- 2 .s
O +-�_.--�._�_.--�._�_.--�._�_+ O
7 6 9 10 11 12 13 14
Frequency (GHz)
Fig. 3. Complex relative permeability and permittivity of hexagonal ferrite
D. Loss Tangent
With eq. (7) and (8) we calculated loss tangent of the material. As we can see in Fig. 4, the losses are higher at the middle frequencies as about 11.5 GHz.
IV. CONCLUSION
The measurement of the electromagnetic parameters of hexagonal ferrite composite material have resulted good complex permittivity and permeability, which were calculated at given thickness according to Nicolson-Ross-Weir (NRW) method from the measurement of the reflected signal (S 11) and transmitted signal (S21). From the results obtained that no anomalies were noticed because resonance in phase for the 1 mm in thickness sample occurs between 7 and 14 GHz. The results overcome a possible disadvantage of using the NR W method. From these results it is possible to conclude that the used procedure obtains a good experimental characterization of magnetic and dielectric of other materials.
30
5 5
4 4
ü r
� c 0 (f) (f)
Cl 3 3 -I
<1l
� Q) :::J
C (]) <0 CD
;;l.
Cl 2 2
c s:
<1l
t-- Q)
<0
(f) :::J
CI) �
0 1
...J 0
0 0
7 8 9 10 11 12 13 14
Frequency (GHz)
Fig. 4. Loss tangent of hexagonal ferrite
ACKNOWLEDGMENT
The authors would like to thank Kementerian Riset, Teknologi dan Pendidikan Tinggi Republik Tndonesia for fun ding under the scheme TNSTNAS 2016 research grant number RD-2016- 0146.
REFERENCES
[I] Devender, S.R. Ramasamy, Int. Conf. Electromagnetic Interference and Compatibility(INCEMIC-97), New Jersey, 7B-7, 1997, pp. 459-466.
[2] W.H. Emerson, IEEE Trans. Antenna Propag. AP-21 (4) (1973) 484- 490.
[3] Hidetoshi Ebara, Takao Inoue, Osamu Hashimoto. Science and Technology of Advanced Materials 7 (2006) 77-83
[4] Rastislav Dosoudil, Elemir USak, Vladimir Olah. Journal of Electrical Engineering, Vo161. No 7/s, 2010, 111-114
[5] Lynch, AC.: Precise Measurements on Dielectric and MagneticMaterials, IEEE Trans. Instrum. Meas. IM-23 (1974), 425- 43 I.
[6] M.C Dimri, S.C. Kashyap, D.C. Dube, IEEE Trans. Magn. 42 (2006) 3635-3640.
[7] F. M. M. Pereira, M. R. P. Santos, R. S. T. M. Sohn, 1. S. Almeida, A M. 1. Medeiros, M. M. Costa, A S. B. Sombra. 2008. Magnetic and dielectric properties of the M-type bariumstrontium hexaferrite (Ba,Sr,.
,FeI20'9) in the RF and microwave(MW) frequency range. J Mater Sci:
Mater Electron.
[8] H.J. Zhang, X. Yao, 1.Y. Zhang, J. Magn. Magn. Mater.241 (2002) 441.
[9] 1. Kreisel, H. Vincent, F. Tasset, P. Wolfers, 1. Magn.Magn. Mater. 213 (2000) 262.
[10] A. M. Nicolson and G. F. Ross. Measurement of the intrinsic properties of materials by time-domain techniques. IEEE Trans. Instrumentation andMeasurement,19,3 77 -382,1970.