Cryogenic W-Band Lna For Alma Band 2+3 With Average Noise Temperature Of 24 K

A cryogenic low noise amplifier that operates across the E and W-bands, from 65 GHz to 116 GHz, has been developed using 0.1-mu m InP HEMT technology. Such wideband performance makes this work suitable for the ALMA telescope where two of its bands, 67-90 GHz of Band 2 and 85-116 GHz of Band 3, can be combined into one. At an ambient temperature of 5.5 K, this W-band LNA demonstrates an average noise temperature of 24.7 K with more than 21 dB gain and +/- 3.0 dB gain flatness from 65 GHz to 116 GHz. To the best knowledge of the authors, this combination of bandwidth, gain flatness and noise temperature has not been demonstrated before.