Showing papers by "Bobby Brar published in 2011"

Low loss cryogenic InAs/AlSb HEMT non-reflective SP4T switch

Abstract: A non-reflective single pole four throw (SP4T) MMIC switch using ABCS InAs/AlSb HEMT process technology, designed for cryogenic temperature has been fabricated and characterized. This switch is suitable for low RF power applications that require very low insertion loss and good isolation. At 2 GHz, the SP4T switch demonstrated 0.52dB insertion loss and 33dB isolation at room temperature. At 90K, the switch has seen 0.2dB and 2dB improvement in insertion loss and isolation. These results demonstrate the outstanding potential of ABCS HEMT technology for low loss switches for cryogenic temperature.

A 3-stage shunt-feedback op-amp having 19.2 dB Gain, 54.1 dBm OIP3 (2GHz), and 252 OIP3/Pdc ratio

Abstract: We report here a 3-stage shunt-feedback configured operational amplifier using simple-Miller compensation demonstrating 19.2dB mid-band S 21 gain, P DC = 1020mW. At 2GHz operation the amplifier shows 54.1dBm OIP3 and a record high OIP3/P DC ratio = 252. Through the use of a 350GHz ƒ r , ƒ max 0.5um InP HBT technology, the loop transmission at low GHz operation provides a large reduction to the closed-loop distortion. The amplifier employs a differential topology, resistive pulldown biasing, large 6nH inductors to act as RF chokes, and a 6-finger (10µm L e ) output stage to increase P out before the onset of waveform clipping. The loop bandwidth is greater than 30GHz, 5.5dB NF, and is unconditionally stable from DC-8.5GHz. The slope-3 breakpoint (S-3BP, where the IM3 spurs are 3dB greater than the expected slope-3 trend) is at P out = 16.6mW/tone. The increases to OIP3/P DC ratio represent > 1.7× betterment in state-of-the-art. The circuit contains 24 HBTs and is 0.92×0.46-mm2.