Accurate microwave dielectric measurement of materials is necessary data for the design engineer during the development stage of electronic and communication components. Several techniques have been published in recent years for measurement of dielectric properties of materials at microwave frequencies. Each of these techniques has some limitations in terms of accuracy and frequency coverage. T...

In transmission-reflection method, the microstrip transmission line coated with an organic polymer as an overlay is used to estimate the permittivity of the polymer film. Scattering parameter response of the microstrip line varies as the permittivity of the overlay or its thickness changes. The permittivity is estimated by minimizing the difference between the theoretical (computed from the ana...

A moisture detection of single rice grains using a slim and small open-ended coaxial probe is presented. The coaxial probe is suitable for the nondestructive measurement of moisture values in the rice grains ranging from from 9.5% to 26%. Empirical polynomial models are developed to predict the gravimetric moisture content of rice based on measured reflection coefficients using a vector network...

We have investigated the effects of electrical conductivity of the constituents on the dielectric and piezoelectric properties of ferroelectric 0-3 composites. The time-dependent internal electric fields are first derived, which can be induced by an applied ac field in dielectric measurement or stress in piezoelectric measurement. Our previously developed model fC. K. Wong, Y. M. Poon, and F. G...

Photonic band-gap (PBG) crystals offer new dimensions of freedom in controlling propagation of electromagnetic waves. The existence of stop-bands in the transmission characteristic of these crystals makes them a suitable element for the realization of many useful microwave and optical subsystems. In this paper, we calculate the propagation constant of a one-dimensional (1-D) photonic crystal by...

Microplasma generated within a millimeter wave (MMW) photonic crystal (PhC) is analyzed by direct measurement of the electron density and transmission spectra (S21) crystal. A continuous (cw) drive frequency 43.66 GHz maintains plasma, while low power sweep (43.5–44.1 GHz) simultaneously probes in presence microplasma. Rotational gas temperature are measured from CH emission spectrum Stark broa...

Mixing models help describe the contribution of liquid, gas, and solid phases to the bulk dielectric permittivity of porous materials. They are particularly useful when studying the electromagnetic properties of the vadose zone using TDR or GPR techniques. The objective of this research was to evaluate the Lichtenecker Mixing Model applied to undisturbed and repacked soil data collected with a ...

in this research, electromagnetic properties of graphene-epoxy nanocomposite up to 3wt% graphene, were investigated in x band. results showed that these nanocomposites do not have significant permeability so that it can be considered equal to 1. however they exhibit high permittivity such that real part of permittivity of 3wt% graphene sample is 8.4 in 8ghz and 6.8 in 12ghz frequencies, which a...