The small signal response and thermal noise spectra in miniband superlattice are investigated. The
properties of hot electron differential mobility, velocity fluctuation, and noise temperature are
determined around a stationary condition. The field and frequency dependent drift velocity, electron
energy, effective mass, and electron temperature are obtained. At low frequencies, noise temperature
increases rapidly with the electric field. Our calculated noise temperatures for miniband superlattice
are in good agreement with the experimental results, with the sample thickness estimated to be
around 4 um.