i was measured the Cp, Z and D with frequency from 1M to 120M Hz using HP impedance analyser. after certain frequency surprising i got negative values due to that i got the negative dielectric constant can any body clarify this i have a doubt on systematic error that may occur in the measurement or else any phase conversion in carriers? i am here with attaching the
Dear Santhosh Kumar ,
Permittivity of ferrite materials should be almost constant up to millimeter
wave frequencies and your results seem do be artificial. On the other hand permeability of ferrites is dispersive and can be negative at certain frequency regions. You can find more information about that in the following overview paper:
Jerzy Krupka 2018 Meas. Sci. Technol. 29 092001,"Measurement of the complex permittivity, initial permeability, permeability tensor and ferromagnetic linewidth of gyromagnetic materials"
Dear Santosh,
What is your ferrite thickness. Sometimes, this negative values comes from due to contact problems in the sample holder.
On the other hand, as Antoni said, the dielectric constant will be constant up to certain frequencies. Please thoroughly check with literature.
I wish you good luck.
Dear Santhosh Kumar
When you are measuring dielectric constant at high frequencies especially beyond 1MHz the cell capacitance should be more than sample capacitance. In such cases you will get negative values of dielectric constant. That is why cell corrections should be taken into consideration. Otherwise use the cell supplied by the instrument maker.
- Badges
- Science topic
- Similar topics
- Engineering
- Electrical Engineering
- Electrodes