A Novel 1–6 GHz Chaotic Signal Oscillator for Broadband Communication Systems

In this paper, a novel Colpitts type chaotic oscillator with dual tuning inductor is presented. The oscillator is based on a single stage common-emitter structure, two tuning inductors are adopted at collector and emitter terminal to tune bandwidth and signal stability of the proposed chaotic oscillator. The inductor on collector is used to compensate high frequency signal degradation caused by the Miller capacitance C_BC. The inductor on emitter is used to balance the signal stability over the whole wide operation bandwidth. Based on above techniques, a broadband chaotic oscillator with over 1-6 GHz operation frequency range is derived and presented. To demonstrate the bandwidth tuning principle proposed in this paper, a single stage chaotic oscillator circuit is designed and manufactured on FR4 substrate. A commercial wideband NPN transistor BFG520 is used to amplify and generate signal. The cut-off frequency of this transistor BFG520 is 9 GHz. The circuit is ultra-compact with only 2.54 × 2.54 cm² area. Measurement results show that this chaotic oscillator has stable oscillation state with ±400 mV maximum voltage amplitude, the fundamental frequency fo is 1 GHz, and the chaotic signal bandwidth is over 1-6 GHz.