J. Piotr Starski

Cryogenic 2-4 GHz ultra low noise amplifier

This paper describes two-stage InP-based cryogenic broadband amplifier with very low noise for the frequency band 1.5-4.5 GHz. For a band of 2-4 GHz at 15 K the measured gain is 30.0/spl plusmn/2 dB and a noise temperature below 5 K. The total DC power consumption of the amplifier is 6.8 mW.

Numerical Investigation of Flip Chip Connections using FDTD Simulations

In this paper we present computer simulations for interconnections between a CPW transmission line and a CPW chip (CPW-CPW), Fig. 1, and between a CPW transmission line and a microstrip chip with the active surface turned upwards from the mother board (CPW-MS), Fig. 3. The location of the bumps and the use of multiple bumps are investigated for both interconnection types.

Two-Finger InP HEMT Design for Stable Cryogenic Operation of Ultra-Low-Noise Ka- and Q-Band LNAs

We investigate the cryogenic stability of two-finger 100-nm gate-length InP HEMTs aimed for Ka- and Q-band ultra-low noise amplifiers (LNAs). InP HEMTs with unit gate widths ranging between 30 and 50

A comparison of cryogenically cooled pseudomorphic and lattice matched InP HEMTs: Implementation in an ultra-low noise amplifier

\mu \text{m}

GaAs Flip Chip Evaluation in the 3 to 110 GHz Range

exhibit unstable cryogenic behavior with jumps in drain current and discontinuous peaks in transconductance. We also find that shorter gate length enhances the cryogenic instability. We demonstrate that the instability of two-finger transistors can be suppressed by either adding a source air bridge, connecting the back end of gates, or increasing the gate resistance. A three-stage 24–40 GHz and a four-stage 28–52-GHz monolithic microwave-integrated circuit LNA using the stabilized InP HEMTs are presented. The Ka-band amplifier achieves a minimum noise temperature of 7 K at 25.6 GHz with an average noise temperature of 10.6 K at an ambient temperature of 5.5 K. The amplifier gain is 29 dB ± 0.6 dB. The Q-band amplifier exhibits minimum noise temperature of 6.7 K at 32.8 GHz with average noise temperature of 10 K at ambient temperature of 5.5 K. The amplifier gain is 34 dB ± 0.8 dB. To our knowledge, the Ka- and Q-band amplifiers demonstrate the lowest noise temperature reported so far for InP cryogenic LNAs.

Cryogenic X-Band Low Noise Amplifiers

A comparison between lattice matched (lm) and pseudomorphic HEMTs (pHEMTs) aimed for cryogenically cooled low-noise amplifiers (LNAs) has been performed. The DC and RF performance of the HEMTs at room temperature (RT) has been investigated. The devices have been tested in a hybrid 4 - 8 GHz LNA. While the gain and noise were superior for the pHEMT compared with the lm HEMT at RT, the noise performance was slightly inferior for the pHEMT when cooled to 20 K. The gain was still higher for the pHEMT at 20 K.