volume | PIER Journals

Abstract

This paper proposes a proof-of-concept circuit of a time-domain reflectometry (TDR)-based non-destructive testing (NDT) circuit. The circuit consists of a broadband six-port reflectometer with an end-fire antenna probe. The broadband operation is achieved by a reduced-size six port reflectometer that uses a special algorithm to extend the frequency of operation beyond the limits between which a normal reflectometer usually used. In addition, a highly-directive antenna probe is proposed to provide a near-constant gain across the bandwidth of operation. By operating the circuit within the frequency range 2.5-7 GHz, it is used to detect gaps of various widths between the back of a polystyrene sample and a metallic plate. Results show clear indication of the gaps' existence in addition to a shift that is associated with the gap width. The proposed circuit proves the possibility of implementing the TDR-based microwave NDT system using a low-cost and compact circuit without the need for bulky and expensive vector network analyzers. This paves the road towards utilizing this technology in real-life scenarios.

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Dr. Nadine Adnan Shaaban

Dr. Ghassan Nihad Jawad