High linear HBT MMIC power amplifier with partial RF coupling to bias circuit for W-CDMA portable application

This paper proposes a high linear two-stage InGaP/GaAs heterojunction bipolar transistor (HBT) power amplifier monolithic microwave integrated circuit (MMIC) using a new, on-chip linearizer for 1.95 GHz wide-band code division multiple-access (W-CDMA) system. The linearizer consists of the base-emitter junction diode of the bias transistor and the RF coupling capacitor. The proposed linearizer remarkably improves gain compression of 18 dB and phase distortion of 20degrees, and negligibly has little insertion power loss, and more importantly it requires no additional die area and no additional DC consumption. The HBT MMIC power amplifier with the integrated linearizer exhibits an maximum output power (P-out) of 30.5 dBm, the power gain of 25 dB, the power added efficiency (PAE) of 51% at the maximum output power under the operation voltage of 3.4 V, and adjacent channel power ratio (ACPR) of -56dBc at P-out of 27 dBm.