Classification of Electronic Devices With Power-Swept Signals Using Harmonic Radar

Classification of Electronic Devices Using a Frequency-Swept Harmonic Radar Approach

“…Both metal-metal junctions and nonlinear circuit components exhibit nonlinear current-voltage (I-V) relationships that cause the re-radiation of RF waves at harmonic frequencies of the incident wave [3][4][5][6][7][8]. The re-radiated RF wave from a nonlinear target depends on the harmonic characteristics of the target, which can be utilized to detect, track, and classify this type of target using harmonic radar [9,10]. One of the significant advantages of harmonic radar is its high clutter rejection; it utilizes re-radiated RF waves at the harmonic frequencies of the transmitted frequency, while echoes and clutter are due to natural obstacles which do not result in re-radiation of RF waves at the harmonic frequencies of the transmitted signal [11,12].…”

“…One of the significant advantages of harmonic radar is its high clutter rejection; it utilizes re-radiated RF waves at the harmonic frequencies of the transmitted frequency, while echoes and clutter are due to natural obstacles which do not result in re-radiation of RF waves at the harmonic frequencies of the transmitted signal [11,12]. In addition, harmonic radar has the potential to yield more information about the target by exploiting re-radiated RF signals at the harmonic frequencies of the transmitted signal with varying power and frequency [2,9]. On the other hand, one of the main challenges in harmonic radar is that the re-radiated signal power at the harmonic frequencies is weak, and thus the signal-to-noise ratio (SNR) on the receiver side is low [13].…”

“…The re-radiated signal from nonlinear devices is analyzed by transmitting different types of waveforms to the targets. Transmitting a single-tone waveform to the device under test and analyzing the harmonics of the fundamental frequency are commonly-used techniques in harmonic radar [9][10][11][15][16][17][18][19][29][30][31][32][33]. Another method is to transmit a two-tone signal to the targets and analyze both the harmonics and intermodulation terms of the transmitted frequencies [4,10,23,33,34].…”

“…In [30], energy levels at the low, middle, and high frequencies of the Fourier transformations of the received power curves at the second, third, and fourth harmonic frequencies were exploited for classification. In [9], the received power values at the second, third, and fourth harmonics were exploited to classify various electronic devices using their statistical and Fourier features in the presence of noise. A linear model was developed and employed in order to estimate the unknown deterministic vector of parameters to be used in distinguishing ECUTs via single-tone transmission case [31].…”

“…Previous studies in the literature have shown that electronic devices with nonlinear circuit components such as diodes, semiconductors, mixers, amplifiers, transistors, etc. can be distinguished and classified by exploiting the harmonic characteristics of these devices, which can be obtained by a harmonic radar receiving the re-radiated wave from these targets [9,10,12,[29][30][31]41]. In this study, we develop a novel method to classify various electronic devices using a frequency-swept harmonic radar (FSHR) approach to exploit frequency diversity, unlike previous studies where either power diversity or spatial diversity was exploited.…”