A Harmonic Radar Simulation With Randomly Weighted Multiple Ports of Radiation for Classification of Electronic Devices

This article develops a technique for the classification of electronic circuits by harmonic radar, which uses reradiation characteristics of electronic circuits at harmonic frequencies. The proposed method is proven to be useful with a realistic simulation model by constructing and analyzing the feature domain of electronic circuits under test (ECUTs). Three distinct types of commercially available RF circuits, namely, FM transmitter, FM receiver, and listening bug, are modeled using the advanced design system (ADS) simulation tool. ECUTs are excited randomly from multiple ports by single-tone time-varying signals with linearly swept signal power. Harmonic response of ECUTs is obtained as the superposition of the collected harmonic data at multiple ports unlike earlier approaches, where a single output node is used. Measured harmonic data for power-swept excitation signals is used to calculate statistical features, such as skewness, kurtosis, and variance for each ECUTs to distinguish. A K-nearest neighbors (KNN) algorithm is used for the classification. Simulation results show that the multiple input–multiple output linearly varying power excitation method and calculated statistical parameters have reliable classification performance for complex electronic circuits.