1.Nanjing Electronic Devices Institute,； 2.National Key Laboratory of Solid-state Microwave Devices and Circuits
Abstract： Based on a technology of 0.15 μm GaAs high electron mobility transistor (pHEMT), a 19~21 GHz high linearity power amplifier MMIC was demonstrated in this paper. In the scenario of signal transmission with high peak-to average power ratio（PAPR）,the efficiency and linearity of power amplifier（PA）have a critical impact on RF front-end performance. The amplifier incorporates a cold-mode linearization circuit cascaded at the power amplifier gate to compensate for the amplifier's phase distortion characteristics, thereby enhancing linearity and efficiency. To address the voltage sensitivity issue of the cold mode, an on-chip active voltage stabilization and temperature compensation bias circuit is employed to expand the dynamic range, reduce large dynamic distortion, and mitigate the deterioration of linearity caused by process variations and external discreteness. The room temperature measured results demonstrate that the achieved saturated output power of 22.3~22.8 dBm with 35.3%~36.5% saturated power-added efficiency (PAE) between 19 GHz and 21 GHz. Especially, the measured IMD3 at 19 GHz, 20 GHz and 21 GHz is below -30 dBc with an output power level of 19 dBm. For a 64-QAM orthogonal frequency division multiplexing signal with 6 dB peak-to-average power ratio and 100 MHz bandwidth,，the PA exhibits an adjacent channel power ratio of -31.9 dBc、-33.2 dBc and -31.2 dBc when the error vector magnitude are 4.32%,、4.13% and 5.3%.
Key words : adaptive biasing circuit；cold-mode,；high linearity,；GaAs
引言
隨著衛(wèi)星通信系統(tǒng)不斷發(fā)展，低頻段頻譜資源日益枯竭,，毫米波頻段的通信系統(tǒng)開(kāi)發(fā)備受關(guān)注。同時(shí)衛(wèi)星通信系統(tǒng)中,，寬頻帶的工作要求以及高峰值平均功率比（Peak to Average Power,，PAPR）調(diào)制信號(hào)環(huán)境對(duì)射頻前端的功率放大器的線(xiàn)性度提出越來(lái)越高的要求[1]?；趯?shí)際應(yīng)用場(chǎng)景的功能需求,，功率放大器不僅需要有充足的飽和輸出功率和效率，而且在回退區(qū)間也期望有較佳的功率性能和線(xiàn)性度[2]。當(dāng)前,，隨著工藝技術(shù)的經(jīng)驗(yàn)積累,，GaAs pHEMT已成為毫米波高線(xiàn)性功率放大器的優(yōu)選可靠方案。
