AN HBT MMIC POWER-AMPLIFIER WITH AN INTEGRATED DIODE LINEARIZER FOR LOW-VOLTAGE PORTABLE PHONE APPLICATIONS

This paper gives a detailed description of a novel linearization techn ique using a transistor base-collector junction diode, The novel linea rization technique effectively improves the gain compression and phase distortion of the heterojunction bipolar transistor (HBT) with no add itional de consumption, leading to highly efficient linear amplificati on of the pi/4 DQPSK modulation signals. An AlGaAs/GaAs HBT monolithic microwave integrated circuit (MMIC) linear power amplifier was fabric ated using the novel linearization technique for the handsets used in the 1.9 GHz Japanese Personal Handy Phone System (PHS), The fabricated HBT MMIC power amplifier exhibits an output power of 21 dBm and a pow er-added efficiency as high as 37% at an operation voltage of 2.7 V, A t this rated output power, the adjacent channel power rejection in +/- 600 kHz offset frequency bands is -55 dBc and the error vector magnitu de is 4.3%. This measured linearity is well within the PHS standard.