;The thesis developed three power amplifiers that were designed in WINTM 0.15-µm GaAs, and 0.25-µm GaN for both C-band and Ka-band operations. Firstly, the transistor characteristics of different processes were simulated to choose the best transistor size and current density. The continuous class-J technique was adapted for high efficiency and broadband matching performance. Finally, these proof-of-concepts were verified by measuring various circuit performances, such as s-parameters, output power, linearity and digital modulation characteristics. The first chip presents a Ka-band monolithic microwave integrated circuit (MMIC) power amplifier in WINTM 0.25-µm GaAs technology. The high-efficiency performance is achieved by using continuous class-J mode for output matching networks and high power matching for both input and inter-stage matching networks. The designed power amplifier achieves a 3-dB bandwidth from 25.5 to 28.6 GHz with small signal gain of 16.63 dB. Continuous wave measurements demonstrate a maximum saturated output power of 27.36 dBm and OP1dB of 26.46 dBm, respectively. The chip size is 1.12 (1.4 × 0.8) mm2. The second chip presents a Ka-band MMIC power amplifier in WINTM 0.25-µm GaAs technology. The high-efficiency and broadband performances are achieved by using continuous Class-J mode for fundamental and second harmonic output matching networks and high power matching for both input and inter-stage matching networks. The amplifier achieves a 3-dB bandwidth from 27.4 to 29.1 GHz with small signal gain of 16.84 dB. Continuous wave measurements demonstrate a maximum saturated output power of 28.15 dBm and OP1dB of 27.04 dBm, respectively. The chip size is 0.988 (1.3 × 0.76) mm2. The third chip presents a C-band MMIC power amplifier in WINTM 0.25-µm GaN technology. The high-efficiency and broadband performances are achieved by using continuous Class-J mode for fundamental and second harmonic output matching networks and broadband matching for both input and inter-stage matching networks. The amplifier achieves a 3-dB bandwidth from 3 to 4.3 GHz with small signal gain of 23.94 dB. Continuous wave measurements demonstrate a maximum saturated output power of 39.62 dBm and OP1dB of 39.6 dBm, respectively. The chip size is 4.342 (2.6 × 1.67) mm2.
