The problem with the power amplifiers is that raising the gain and output power may affect the other amplifier factors specially in the frequency ultra-band. This paper presents a CMOS power amplifier (PA) for Ultra-Wideband (UWB) applications in 2.2 to 5 GHz using two stages of common source topology with derivative superposition (DS) method. Simulation results show an average power gain of27.2 dB with an input 1dB compression point (1dB-CP) of -14.6 dBm at 3.2 GHz and an output 1dB compression point (1dB-CP) 12.9 dBm. With an input power of 83.8 mW, from a 1.8 V supply, power added efficiency (PAE) is 47.5% at 3.2 GHz with 50Ω load impedance and stability factor is 7.2 at 3.2GHz. The proposed design has been simulated using TSMC 0.18µm technology. The important parameters that define an RF Power Amplifier are: Output Power, Gain, Linearity, Stability, DC supply voltage, Efficiency, Ruggedness. The design results showed high power output without affecting the other amplifier factors. A comparison with the previous research has been done and the comparison is clearly in favor of the present design.