High-linearity, low DC power GaAs HBT broadband amplifiers to 11 GHz

Two broadband hybrid amplifiers based on GaAs heterojunction bipolar transistors (HBTs) have been developed covering the 0.05-11-GHz frequency band. These amplifiers represent the first reported balanced and distributed HBT amplifiers and offer significant improvement over MESFET and HEMT approaches in high linearity, low DC power performance for space communication applications. A 5-11-GHz balanced amplifier designed for high linearity produces +32-dBm third-order output intercept point (IP3) with a 8-dB associated gain and less than 150-mW DC power consumption. The balanced architecture permits easy cascadability and allows optimum impedance match design within the Lange couplers. A 0.05-9-GHz distributed amplifier designed for low DC power and high gain consumes only 50 mW and provides 10-dB flat gain. On the basis of these hybrid designs, monolithic heterostructure bipolar transistor (HBT) amplifiers have been designed which offer the potential for improved capabilities.<
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