# 분말재료의 복소 유전율 및 투자율 측정

• 박상복 (서울시립대학교 전자전기컴퓨터 공학부) ;
• 이장수 (서울시립대학교 전자전기컴퓨터 공학부) ;
• 정용식 (광운대학교 전파공학과) ;
• 천창율 (서울시립대학교 전자전기컴퓨터 공학부)
• Published : 2007.12.01

#### Abstract

Materials used at microwave are usually used as a dielectric with a manufacturing purpose of printed circuit boards, etc. Complex permittivity of them can be measured from attenuation constant or propagation constant of a transmission line using a microstrip line with bulk type. But as the technique recently which can manufacture to have complex permittivity and permeability demanded using nonferrous metals for powder-type grows up, we need sensors and methods which can measure characteristics of powder-type materials. So far measuring methods of permittivity and permeability with waveguide or coaxial cable are used but they have faults which have a complex measurement method and are difficult to simultaneously measure permittivity and permeability. In this paper, a simultaneous measuring method of permittivity and permeability with 2-port coaxial cable and a new proposed calculation. The proposed 2-port coaxial cable is designed to be easy to insert materials and to have a wideband. We measure permittivity and permeability of magnetic powder(Ni-Fe-Mo, Ni-Fe) which reveal its characteristic at $0.3{\sim}1.3GHz$ to identify the proposed sensor.

#### References

1. A. Nyshadham, C.L. Sibbald and S.S. Stuchly, 'Permittivity measurements using open-ended sensors and reference liquid calibration - An uncertainty analysis,' IEEE Trans. Microwave Theory & Tech., vol. 40, no. 2, pp. 305-313, 1992 https://doi.org/10.1109/22.120103
2. William B. Weir, 'Automatic Measurement of Complex Dielectric Constant and Permeability at Microwave Frequencies', Proceedings of IEEE, vol. 62, No.1, January 1974