A study of linearity improvement for microwave power amplifier

• Main Authors: I-Hsiang Tsai, 蔡翊翔
• Other Authors: Yue-Ming Hsin
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/32797415284453136774

碩士 === 國立中央大學 === 電機工程研究所 === 98 === The research content divides into two parts: First, measured GaAs-based heterojunction bipolar transistor amplitude-to-amplitude (AM-AM) and amplitude-to-phase (AM-PM) characteristics. Obtain the power series coefficients of output voltage real part and image part versus input voltage to describe the transistor non-linear characteristics using a formulation. After calculation can prediction the transistors output spectrum characteristics and adjacent channel power ratio under different output power with a CDMA IS-95 signal. Secondly, a 3.5 GHz linearity power amplifier in WIN 0.5 μm pHEMT process, a common gate transistor can adjust power amplifier bias to improve linearity. The power amplifier exhibits power gain of 11 dB, saturation output power of 29 dBm, maximum power-added efficiency of 31 %. A 2.4 GHz linearity power amplifier in TSMC 0.18 μm CMOS process, the feed-forward device offer second harmonic signal injection route to improve linearity. The power amplifier exhibits power gain of 16 dB, saturation output power of 21 dBm, maximum power-added efficiency of 17 %. The measured error vector magnitude was 5.6 % under an output power of 12 dBm using 2.4 GHz IEEE 802.11 g OFDM 64-QAM signal.