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UBC Theses and Dissertations

On the design of highly linear efficient millimeter-wave power amplifiers and ultra-wideband low-error phase shifters for emerging wireless communication applications Asoodeh, Alireza


With the unprecedented growth in the number of connected devices and demand for larger amount of data as well as higher data rate, there is a need to improve our communication systems to address such demands. Addressing these demands have resulted in devising a roadmap for transition from current 4th generation of communication systems (4G) to the 5th generation (5G) and beyond 5G in the near future. To address the demand for higher data rates, broadening the frequency spectrum of 5G and beyond 5G to millimeter wave bands is being actively pursued. To overcome propagation losses, reduce interferers and improve signal-to-noise ratio, phased-array systems have attracted a lot of attention especially for applications operating in mm-wave bands. In this work, we mainly focus on two important building blocks of phased-array systems, namely, power amplifiers (PAs) and phase shifters. To fulfill the stringent linearity and efficiency requirements of the 5G and beyond 5G systems, a linear and efficient PA is required. We present several design techniques for implementing highly linear and efficient CMOS PAs. The proposed techniques include strategic placement of varactors, a multi-function coplanar-waveguide (CPW)-like power combining structure, and a systematic design approach for the passive networks. A proof-of-concept prototype that operates in the 28 GHz band is designed and fabricated in a 65-nm bulk CMOS process. The design achieves a Psat of 23.2 dBm, output P1dB of 22.7 dBm, and power-added efficiently (PAE) of 35.5%. Next, a continuous-mode 360˚ mm-wave ultra-wideband phase shifter over the frequency range of 10 GHz to 50 GHz is presented. A proof-of-concept prototype is also designed and fabricated in a 65-nm bulk CMOS process. To implement such an ultra-wideband phase shifter, design approaches for several key building blocks including balun and quadrature all-pass filter (QAF) are proposed. These sub-blocks are separately analyzed. To confirm the validity of the proposed techniques, proof-of-concept prototypes have been designed and tested. Particularly, the continuous-mode 360˚ phase shifter prototype achieves ~0.2-dB root-mean square (RMS) amplitude and <1.4˚ phase error over the frequency range from 10 to 50 GHz.

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