A 2-50 GHz InAlAs/InGaAs-InP HBT distributed amplifier

摘要

Here we report on a 2-50 GHz InAlAs/InGaAs-InP HBT Distributed Amplifier (DA) which demonstrates the highest frequency of operation so far reported for a wideband HBT amplifier and is a 10 GHz (25%) improvement over previous state-of-the-art. The amplifier features 1/spl times/4 /spl mu/m/sup 2/ single-emitter HBTs with a base under-cut structure for reducing the device's collector-base capacitance C/sub bc/, resulting in as much as a 20% improvement in device f/sub max/ performance. The MMIC is a 5-section coplanar waveguide distributed amplifier design which employs HBT cascode devices. Previous work using non-undercut HBTs has resulted in 5.5 dB gain and 2-32 GHz BW performance. In the present work, the HBT DA obtains a peak gain of 6.3 dB with a bandwidth beyond 50 GHz while operating from a 4 V supply and consuming only 89 mW of DC power. The gain is 4.1 dB at 30 GHz, 3.9 dB at 40 GHz and 4 dB at 50 GHz. An open circuit transimpedance of 45 dB-/spl Omega/ calculated from S-parameters is achieved with an upper band edge of 50 GHz. The corresponding effective 5O-/spl Omega/ loaded transimpedance is 39.2 dB-/spl Omega/ also has an upper band edge of 50 GHz. The wideband gain and transimpedance results here benchmark the highest bandwidths so far recorded for either HBT or BJT amplifiers and suggests the capability of InAlAs/InGaAs HBTs for millimeter-wave and high data rate (40 Gbps) IC applications.