A novel chaos based pulse amplitude modulated ultra-wide band (CPAMUWB) imaging radar was presented. The proposed radar has good range resolution and excellent range side lobe suppression characteristics that enhance its imaging performance, better than that of the conventional time modulated UWB (TMUWB) radars in reducing false alarms. Numerical electromagnetic (EM) simulations using finite difference time domain (FDTD) method illustrate the definite advantages of the proposed radar under different scenarios.