Design of CMOS Power Amplifier for Millimeter Wave Systems at 70 GHz

In this paper, a new CMOS power amplifier that can operate at 70 GHz is designed and developed. The advantages of using 70 GHz at millimeter wave (mmW) band is the huge amount of bandwidth available for various purposes whether they are in the cellular industry or manufacture devices such as high bandwidth wireless LAN and low attenuation of bandwidth frequencies around 70 GHz bands comparing with 60 GHz. Design power amplifiers at 70 GHz are quite challenges task. The complication such as the stability of the amplifier is difficult and hard to be achieved. In this paper, we design power amplifier with 3 single ended, common source stages biased in class A. The proposed circuit resulted in a stable power amplifier capable of working at 70 GHz frequency. The purpose of using three stages is not only to maximize gain but also to increase isolation against reflections. We found that this configuration has many advantages in terms of lower power supply required, leading to higher efficiency and good linearity. The first stage is biased at a peak Fmax biased of 0.2 mA/μm to maximize the gain to 10.58 dB. The second and third stages are biased at optimum linearity current density of 0.28 mA/μm. KeywordmmW, Power amplifier, Radio frequency, CMOS