A cross-coupled chaotic signal generator circuit is presented. Chaotic oscillation conditions of the cross-coupled circuit are proved through establishing nonlinear chaotic model. The stability enhancing mechanism of left-and-right complementary property is analyzed by splitting the cross-coupled circuit into two complementary two-stage chaotic circuits. The chaotic attractor and output spectrum are simulated and tested by tuning the port impedance. Results show that, the stable chaotic output impedance of the cross-coupled chaotic circuit is below 80 Ω, the stability is enhanced by 6 times than that of the conventional circuit with 500 Ω output impedance. The output chaotic signal spectrum is divided into three bands covering 1.5~11.4 GHz, which is enhanced by 50% than that of the conventional circuit.