A New Method for Evaluation of Thickness and Monitoring Its Variation of Medium- And Low-Loss Materials

Abstract

Abstract-In this research paper, we propose an amplitude-only method for unique thickness evaluation of medium-and low-loss materials. The method is based on using amplitude-only measurements at different frequencies to evaluate the unique thickness. Main advantages of the method are a) it eliminates the necessity of repetitive measurements of different-length materials to evaluate the unknown thickness of the same type material and b) it determines the thickness at any desired frequency in the band. Because the method uses amplitude-only measurements and enables the thickness evaluation at any frequency, it can be a good candidate for thickness evaluation of materials in industrial-based applications.

A microwave method based on amplitude-only reflection measurements for permittivity determination of low-loss materials

“…4, when compared to that in Fig. 9, shows the higher sensitivity of the proposed method for measurement of thickness or monitoring its change for a known (or given) e r of low-loss materials [6,65] since any small variation in thickness could be monitored or detected with a high accuracy. The same reasoning we made for the analysis for the effect of a small offset in jS 11 j on e r extraction applies here for the physical understanding.…”

A Microwave Sensor for Evaluation of Plastic Wall Thickness

“…Delay through the material is a function of the material total length and can be used to resolve this ambiguity. Measurements at two different frequencies can also be used to solve the phase ambiguity problem [2,3].…”

“…Many techniques (transmission/reflection line, free space, open ended coaxial or waveguide probe) have been developed to measure these properties such as techniques in time domain or frequency domain with one port or two ports, etc. Every technique is limited to specific frequencies, materials and applications [1][2][3]. However, in some industrial processes used materials have a low permittivity or high loss; opposite wall is not metal-backed and only one side of materials is accessible.…”

Retrieval of Effective Electromagnetic Parameters of Isotropic Metamaterials Using Reference-Plane Invariant Expressions

“…8). This effect arises from the fact that Re {ε r } and Re {µ r } are mainly influenced by a phase shift, whereas Im {ε r } and Im {µ r } are chiefly altered by an amplitude change for low-loss materials [31]. d) Effects of offsets from true of L 1 and L 2 are generally lower near resonance region for Composite MM slabs than for SRR MM slabs (Figs.…”