The Spin-wave Measurement Of The Medium Material Parameters Studied

Though chiral medium was discovered since last century, many problems aboutsuch kind of complex medium still left for research. Recently, with the advancementof modern measurement, the improvement of the calculational quality, and thedevelopment of hyper-synthesis techniques and polymer engineering, many difficultproblems can be solved successfully. So, more and more researchers focus theirinterest on further applying such kind of complex medium.Through analyses of the correlative measurement technology and consideration ofthe characteristic of the measured materials, the free-space measurement method andthe physical model are built. The transmission properties of electromagnetic wave infree-space are discussed based on Maxwell formulae and the constitutive relations ofchiral medium. The measured materials are regarded as two-port networks andthrough theory analysis, the relations between material parameters of chiral mediumand S-parameters are formulated.Free-space measurement system is built after theory analysis, and the calibrationkits used in this system are fabricated. The TRL calibration technique and thetime-domain gating feature of the network analyzer are used to eliminate the effects ofundesirable multiple reflections. Automatic test software is complied to control themeasurement system and calculate material parameters. Material samples are testedby this system and the software in the frequency rang of 8-12 GHz, the resultsindicate that the method is correct, and the test system is reliable. So, the testtechnique can be used for the automatic, rapid, accurate, broad-band, andnondestructive measurement of material parameters of chiral medium, and it is verypractical.