Chaotic Colpitts Oscillator for the Ultrahigh Frequency Range

PSpice simulation and experimental results demonstrating chaotic performance of the Colpitts oscillator in the ultrahigh frequency (300–1000 MHz) range are presented. Various combinations of the resonance tank parameters are considered to achieve a fundamental frequency as high as possible. Simulations indicate that chaotic oscillations observed experimentally at higher frequencies, e.g., at about 1000 MHz are caused by parasites, like wiring inductances, loss resistance appearing due to skin effect, and collector-emitter capacitance of the transistor. Reliable and reproducible chaos can be generated at fundamental frequencies up to about 500 MHz with the single-stage Colpitts oscillator using the microwave 9 GHz bipolar junction transistors.