Nonlinear Through-the-Wall Detection Using DORT Applied with LFM Pulses

• Published in: IEEE antennas and wireless propagation letters Vol. 22; no. 6; pp. 1 - 5
• Main Authors: Cha, Kyuho, Park, Hong Soo, Hong, Sun K.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.06.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Chirp; DORT; Eigenvalues; Eigenvalues and eigenfunctions; Eigenvectors; Focusing; Harmonic analysis; harmonic radar; Harmonics; Nonlinear detection; Power harmonic filters; Receiving antennas; selective focusing; Target detection; through-the-wall detection; Time-domain analysis
• ISSN: 1536-1225; 1548-5757
• DOI: 10.1109/LAWP.2023.3241637

The detection of visually obstructed small nonlinear targets in a through-the-wall (TTW) environment is difficult because of linear scatterers and strong wall reflections. In this letter, harmonic-based nonlinear TTW detection is introduced as a method to effectively detect small nonlinear targets behind the wall. Nonlinear TTW detection allows for the suppression of linear scatterer responses and wall reflections by detecting only the harmonics generated from nonlinear targets. Here we apply the decomposition of the time-reversal operator (DORT) for the detection and separation of multiple nonlinear targets behind the wall. DORT extracts the eigenvalues and eigenvectors of nonlinear targets and allows for selective focusing (imaging) of each detected target. In addition, we utilize linear frequency modulated (LFM) pulses, which allow for the compression gain in the detection processing. To validate the proposed concept, we conducted simulation and measurements of various configurations of nonlinear TTW detection. The results demonstrate that nonlinear targets behind the wall can be effectively detected and located.