Millimeter-wave power amplifiers in CMOS silicon on insulator technology
Abstract
The advancing of technology and downscaling of channel length lead to higher operating frequency of the CMOS devices and has enables higher gain at mm-wave frequencies. Silicon transistors nowadays compete with III-V technologies for low-power mm-wave applications. With advantages of low cost, high reliability, high thermal conductivity and the possibility of integration with baseband, digital and signal-processing circuits, Si mm-wave modules have become extremely attractive. In spite of all these advantages, mm-wave Si modules have not yet been realized due to small transistor breakdown voltage caused by downscaling. Small breakdown voltage sets a hard limit on the output power and efficiency of power amplifiers required in mm-wave transmitters. This thesis aims at designing high power and high efficiency power amplifiers at mm-wave frequencies (35GHz). CMOS Silicon on Insulator (SOI) technology with electrically isolated transistors is utilized for the implementation. Dynamically-biased CMOS SOI Cascode transistors are stacked on top of each other to increase the total output voltage swing, output impedance matching and output power without causing instability and gate oxide breakdown. Series connected transformers are used at the input to provide input signal coupling and high input impedance matching. Due to the low resistivity substrate, parasitic capacitances become a significant issue especially at mm-wave frequencies. Several solutions are proposed for the design of Class-AB power amplifiers at 35GHz. Simulation results that include the effect of all parasitic components show that overall output powers of higher than 100 mWatt and power added efficiencies exceeding 30% can be achieved.
Degree
M.S.E.C.E.
Advisors
Mohammadi, Purdue University.
Subject Area
Electrical engineering
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