EVALUATION OF DIFFERENT ANTENNA AND DATA ANALYSIS CONCEPTS FOR MICROWAVE BASED NON-DESTRUCTIVE TESTING

Speaker:
Nestrov, M.; ifak – Institute for automation and communication; Germany

Authors:
Nestrov, M.; ifak – Institute for automation and communication; Germany
Bendler, M.; Magdeburg-Stendal University of Applied Sciences; Germany
Hantscher, S.; Magdeburg-Stendal University of Applied Sciences; Germany
Auge, J.; Magdeburg-Stendal University of Applied Sciences; Germany
Wöckel, S.; ifak – Institute for automation and communication; Germany
Gagelmann, T.; ifak – Institute for automation and communication; Germany

ID: ECNDT-0106-2018
Download: PDF
Session: Microwave, Terahertz, and Infrared NDE
Room: H1
Date: 2018-06-13
Time: 15:20 - 15:40

Continuous wave measurements at 24 GHz are a simple and cost-efficient method for microwave based non-destructive testing (NDT) of dielectric materials (e.g. plastics, wood, composites). To provide high-resolved and accurate results the near-field radiation characteristics of the used antennas have to be studied. These include, among other, the antenna footprint, return loss, polarization and focusing characteristics of the radiated waves to detect defects in different depths in plastic materials.
For this purpose, an open waveguide, a tapered waveguide and a patch antenna on FR4 are simulated, measured, tested and evaluated.
The antenna characteristics are simulated using 3D FEM solvers. The results are used to optimize important model parameters like taper insertion depth or the dimensions of the patch antenna. Afterwards, the antenna concepts are verified by network analyzer measurements as well as by using real samples for NDT applications. The results are compared in terms of penetration depth and resolution.
A second focus is on the visualization of the acquired data, especially the image post processing.
One of the main problems of near field measurements are diffraction patterns which makes detection of defects and edges more complicated or leads to the detection of non-existent defects due to wave interferences in the finale image. The main goal is to eliminate these diffraction patterns by using mathematical algorithms. First results are presented in this paper.