High Efficiency Power Amplifiers for 77GHz Automotive RADARs

Automotive RADARs have gained popularity recently as a means to sense obstacles and avoid collisions, thus preventing loss of life related to vehicular incidence. Research in object detection is increasingly tending towards the 77GHz automotive RADAR band, owing to the availability of larger bandwidths, resulting in high range resolution. Another advantage of the frequency band comes from the absorption properties of the atmosphere, which limits the range and allows multiple vehicles to use RADARs with minimum interference.A Power Amplifier is the most power hungry block in a transmitter-receiver chainand must be designed for high power efficiency, in order to mitigate radiative and more importantly heat losses. However, achieving high efficiency within the target automotive RADAR band proves to be challenging, specifically in case of integrated CMOS PAs. This thesis presents a study of Injection Locked Power Amplifiers (ILPA) in detail and proposes an architecture to meet the RADAR specification. The thesis also highlights passive loss models and provides a theoretical analysis of multi-stage power amplifiers by deriving an expression for the total efficiency of such a PA.Furthermore, this thesis proposes a design procedure and highlights the design process in 40nm CMOS technology. Emphasis is also placed on the study of the active device available in the PDK. The designed integrable PA shows a peak output power of 13dBm with a PAE=17% and gain=16dB within a 5GHz band centered around 78.5GHz