By Pallavi Malame

Dr. Rajiv Gupta , HOD Electronics and Telecommunication , Terna college of Engineering, Project Guide

Tapas K. Bhuiya , Project Guide at Society for Applied Microwave Electronics Engineering and Research SAMEER, MUMBAI and Staff at SAMEER.

Interaction of a material with an electric field

DIELECTRIC CONSTANT :measure of how much energy from an external field is stored in a material

LOSS FACTOR :measure of how dissipative or lossy a material is to an external field

LOSS TANGENT :the ratio of the imaginary part of the dielectric constant to the real part.

Waveguide fixture method comes under a broad concept of dielectric spectroscopy.

Describes the dielectric properties of a sample as a function of frequency

A material’s dielectric properties are determined by its molecular structure.

Other properties of interest can be correlated to dielectric properties

Can be used to measure Moisture content, Biomass, Bulk density, Bacterial content ,Cancer detection, Chemical reaction ,Mechanical stress, Structure, Consistency, Concentration, Fruit ripeness and other physical properties …

A typical transmission line system consists of a vector network analyzer, with appropriate calibration kit, and a sample holder connected between the two network analyzer ports.

Calibration must be carried out before making the measurement.

The method involves measurement of the reflected (S11) and transmitted signal (S21).

S11 & S21 ε (permitivity)

Measurements are setup in minutes and made in seconds providing real time data

Accurate

Best for solid and granulated samples

Can be modified for online and in vitro measurements

Has varied applications

Computer (not required

for PNA)

85071E

Materials

Measurement

Software

Sample holder connected between transmission line

sensors

l

Reflection

(S )11

Transmission

(S )21

TE waves at 5.81 GHz without any MUT(εr'=10)

TE waves at 5.81 GHz without any MUT(εr'=1)

Simulation of the Transmission line based method and practical results of the fabricated system.

Waveguide design in HFSS

Simulation

Experimental setup

SAMPLE

Fire wood Industry

Wood pulp and paper industry

Brix content measurement

Metamaterials dielectric and permeability measurement

PCB substrate dielectric measurement

Materials in powdered form can also be measured