Millimeter-wave, cryogenically-coolable amplifiers using AlInAs/GaInAs/InP HEMTs

The cryogenic performance of AlInAs/GaInAs/InP 0.1- mu m high-electron-mobility transistors (HEMTs) is reported. Collapse-free DC operation is observed down to the ambient temperature of 18 K. The application of these devices to Q- and E-band low-noise, cryogenically coolable amplifiers is demonstrated. The measured noise temperature of 15 K (noise figure of 0.2 dB) for a multistage 40-45-GHz amplifier with 33 dB of gain at the ambient of 18 K is in close agreement with the prediction of a simple noise model. A very low power consumption per stage of less than 1 mW is recorded. The noise temperature of the E-band cryogenic amplifier is less than 47 K at 70 GHz, demonstrating that the performance of HEMT receivers is now competitive with that of SIS (superconductor-insulator-superconductor) receivers in the 3-mm wavelength atmospheric window.< >