Research of Millimeter-wave Low-Noise Amplifier and E-mode and D-mode GaAs Power Amplifiers for 5G Wireless System Applications

There are many researches on millimeter-wave frond-end amplifiers for developing 5G wireless systems in recent years. The demands of high-speed internet and the shortage of the bandwidth have motivated the designers to explore millimeter wave (mm-wave) frequency with broader bandwidth for 5G cellular applications. This thesis is divided into three parts. The first part presents the researches on high linearity low noise amplifiers for RF frond end. This low noise amplifier fabricated in 65-nm CMOS process with distributed derivative superposition (DS) linearization technique is to improve spectral efficiency in the high speed wireless communication systems. This high linearity LNA provides an adequate gain of 21.2 dB and obtains the average noise figure of 4.87 dB in the desired band. Also, the IIP3 of the proposed LNA with linearizer has been improved 4-6.5 dB from 36 to 40 GHz. The second part of the thesis is the proposed PA fabricated in 0.15-µm enhancement mode (E-mode) GaAs PHEMT with different matching methods. Due to the output power influenced by the gate leakage current, the gate bias circuits are bypassed through a AC-grounded short stub rather than through a large resistor. The PA has Psat of 24.4 dBm with 29.4 % PAEmax and OP1dB of 23.8 dBm and provides an adequate gain of 16.1 dB within 37 to 39 GHz. Finally, a 38 GHz power amplifier (PA) using 0.1-µm depletion mode (D-mode) GaAs PHEMT process is reported. Utilizing 4-way direct-combining technique is to achieve watt-level output power in this two-stage PA design. The large-signal performances of the proposed PA achieves Psat of over 30 dBm, better than 26.5 % PAEmax and over 28.2-dBm OP1dB from 37 to 40 GHz. Also, it provides an adequate gain of 15.1 in the desired band.