Abstract: In order to meet the requirements of chaotic signal sources for ultra-wideband chaotic communication systems, a new two-stage ultra-wideband chaotic circuit design is proposed to improve the bandwidth of chaotic signals effectively. Compared with the classic Colpitts chaotic circuit structure, the new structure uses an emitter follower with a collector inductor as the signal output end and introduced high-frequency resonance network. Thereafter, the signal power spectral density is compensated at high frequencies and the bandwidth was extended. The numerical solution of the new two-stage ultra-wideband chaotic circuit is obtained by MATLAB, and the bifurcation diagram and phase diagram of the new ultra-wideband chaotic circuit are obtained. The time domain diagram, spectrum diagram of the circuit output are also obtained through simulation analysis. It is shown that the new two-stage ultra-wideband chaotic circuit can generate 7.5 GHz wideband chaotic signal with a power within 20 dB, which meets the requirements of ultra-wideband signal indicators(3.1~10.6 GHz) for chaotic signal sources.

Key words: ultra-wideband chaotic communication, chaotic signals, Colpitts chaotic oscillator, emitter follower, collector inductance