Noise bandwidth of diffusion-cooled hot-electron bolometers

Abstract

We present studies of the input and output noise of diffusion cooled hot-electron bolometer mixers. By simultaneously measuring the gain and noise (-with a 14 GHz LO) as a function of intermediate frequency for a 0.16 μm diffusion cooled Nb device we show that the noise bandwidth (4 GHz) is larger than the gain bandwidth (2.4 GHz). The output noise is 55 K and the mixer noise is very low 340 K DSB. This shows that diffusion cooled devices have low noise over a broad enough intermediate frequency band for practical applications in THz receivers. © 1997 IEEE.