A Variable-Resolution Amplitude–Frequency Response Measurement Method Based on Multimode RF Chaotic Signals

This article proposes and experimentally validates a variable-resolution amplitude–frequency response measurement method utilizing multimode radio frequency (RF) chaotic signals. Based on the compressive sensing (CS) theory, this method employs multimode RF chaotic signals to achieve compressed sampling and greedy iterative reconstruction of the response of the device under test (DUT). The key innovation lies in generating multimode RF chaotic signals by mixing a fundamental RF chaotic signal with single-tone RF signals. Meanwhile, a fusion reconstruction algorithm is proposed to improve measurement accuracy. Leveraging the broadband continuous spectrum of chaotic signals, the method achieves variable-resolution reconstruction within a single measurement. Experimental results demonstrate a 0.6–3.0-GHz measurement system reconstructing 101-point responses from 50 samples with a 2.02 compression ratio. Numerical simulations and physical experiments on 0.915-and 1.890-GHz bandpass filters validate the fusion algorithm’s capability for global reconstruction (24-MHz resolution) and local reconstruction (8-MHz resolution). Compared with conventional single-tone scanning methods, the proposed method reduces sampling operations by 50.5% while maintaining low hardware complexity. Unlike low-resolution global scanning that may miss narrowband targets, this method ensures detection reliability while enabling variable-resolution ability in a single measurement. The proposed method shows potential for electromagnetic target characterization applications.