一种带功率检测和自适应偏置的CDMA功率放大器

A CDMA Power Amplifier with a Power Detector and an Adaptive Linear Bias Circuit

设计了一款包含功率检测和自适应线性化偏置电路的CDMA功率放大器,功率检测器能根据输入信号的大小来调整功率管的偏置点,大幅提升低功率输出时的效率,从而提升系统整体效率;自适应线性化偏置能有效抑制功率放大器的增益压缩和相位失真,改善其线性度。采用2μm InGaP/GaAs HBT晶体管工艺成功流片,测试结果表明,与普通功率放大器相比较,当输出功率小于10 dBm时,新型功率放大器的集电极电流大幅降低,系统整体效率提高了2.2倍;1 dB增益压缩点由30 dBm增加到32 dBm;当输出功率为28 dBm时,ACPR和ALTR分别改善了5 dB和12 dB,IM3改善了11 dB。

A CDMA power amplifier with a power detector and an adaptive linear circuit is designed.The power detector is used to adjust the bias point according to the input signal amplitude,which increases the efficiency when the output power is low and further more increases the system total efficiency.The adaptive linear circuit can efficiently improve the linearity by suppressing gain compression and phase distortion of the power amplifier.Measurement results of this novel amplifier fabricated based on 2 μm InGaP/GaAs HBT technology show that： the collector current is considerably reduced when the output power is less than 10 dBm and the system total efficiency reaches up to 2.2 times compared with the conventional amplifiers.The 1 dB compression point rises up from 30 dBm to 32 dBm.The ACPR,ALTR and IM3 are improved by 5 dB,12 dB and 11 dB respectively when the output power is 28 dBm.