Generation of Uncorrelated Multi-channel Chaos by Electrical Heterodyning for Multiple-input-multiple-output Chaos Radar (MIMO CRADAR) Application
Chih-Hao Cheng1*, Yi-Cheng Chen1, Fan-Yi Lin1
1Institute of Photonics Technologies, Department of Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan
* presenting author:Chih-Hao Cheng,
Multiple-input-multiple-output (MIMO) radar has received much attention in recent years for its great ability in imaging. However, the essence of MIMO radar has not been fully implemented owing to the lack of proper transmission waveforms. In MIMO radar, the transmission waveform of each channel has to be uncorrelated with each other to avoid cross-interference between channels. To achieve this, we investigate the generation of uncorrelated multi-channel chaos using electrical heterodyning for MIMO chaos radar (MIMO CRADAR) application. By electrically heterodyning a seed chaos source with multiple single-frequency local oscillators, chaos with different heterodyned spectra can be extracted and converted into multiple chaos channels. In this paper, the correlations between different channels of chaos generated are analyzed both numerically and experimentally. The minimal frequency spacing of the local oscillators for generating the largest amount of uncorrelated chaos channels is discussed. In our analysis, thousands of uncorrelated chaos channels can be simultaneously generated with a correlation time of several μs. Moreover, compared with those conventional waveform-designing methods which require complicated optimization and digital-to-analog conversion (DAC), the proposed heterodyned technique shows for the first time that multiple uncorrelated channels can be generated in real-time while breaking the bandwidth limitation of the DAC devices. A proof-of-concept experiment is successfully demonstrated to show the feasibility of using the multi-channel heterodyned chaos in the MIMO CRADAR application.

Keywords: Semiconductor lasers, Instabilities and chaos, Heterodyne, Radar