الفهرس 
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Abstract
This thesis compares between different power amplifiers (PAs) architectures used in
millimeter wave (mmWave) communications. Modern high order modulation schemes
such as: orthogonal frequency division multiplexing (OFDM) and quadrature amplitude
modulation (QAM) have high peak to average power ratio (PAPR), which require a high
efficiency at the power back-off (PBO) and a linear PA with a small difference between
the saturated power (Psat) and the output 1dB compression point (OP1dB).
Class AB PAs suffer from amplitude to amplitude modulation (AM-AM) distortion due
to the non-linearity within the PA stage. In addition, they suffer from the amplitude
to phase modulation (AM-PM) distortion because of the nonlinear capacitance of the
input stage. A pre-distorter introduces an expansion behaviour of the gain versus the
input power to overcome the inherent compression AM-AM distortion of the PA, while
a varying phase element is integrated to compensate for AM-PM distortion. The correct
analysis of the conventional cold-FET is provided, where the transistor enters the saturation region during the first half cycle, hence, the change in the resistor value is limited
and the increase in OP1dB is limited. Depending on this analysis, another configuration
of the cold-FET is presented with a capacitor in parallel to compensate for the AM-AM
and AM-PM distortions, respectively.
The two stage class AB PA is designed in 65nm CMOS technology node using 2V supply.
The frequency range is the 5G band from 24 GHz to 30 GHz. The proposed cold-FET
and the proposed capacitor are integrated with the PA to improve the AM-AM and AMPM distortions. The small signal gain for the PA is 18 dB with the proposed cold-FET.
The Psat is 16.5 dBm, the OP1dB expands by 1.8 dB with a 3.1% enhancements in its
PAE compared to the case without the cold-FET. The difference between the Psat and
the OP1dB is 1.5 dB.