Third-order Intermodulation Reduction in Mobile Power Amplifiers by the First Stage Bias Control
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In this paper, the third order intermodulation distortion (IMD3) of three-stage power amplifier (PA) is analyzed using the Volterra series. The analysis explains how the total IMD3 of the three-stage power amplifier can be reduced by the first-stage bias condition. The three-stage PA, which is fabricated using InGaP/GaAs hetero-junction bipolar transistor (HBT), operates with an optimized first driver stage bias for higher P1dB and good gain flatness. The power amplifier has been designed for 1626.5 MHz~1660.5 MHz satellite mobile communications. With π/4 DQPSK modulation signals, this PA can deliver a highly linear output power of 33 dBm from 3.6V supply voltage. At 33 dBm output power, it shows a gain of 31.9 dB, a power-added efficiency (PAE) of 39.8%, an adjacent channel power ratio (ACPR) of -28.2 dBc at a 31.25 KHz offset frequency.
KeywordsSatellite mobile phone, first driver stage bias, three-stage power amplifier (PA), high 1 dB gain compression point, IMD reduction
Document typePeer reviewed
Document versionFinal PDF
SourceRadioengineering. 2012, vol. 21, č. 2, s. 746-751. ISSN 1210-2512
- 2012/2