Ka-band HEMT-based low noise amplifier modules

A two-stage low noise amplifier module for the 35.5 - 36.5 GHz band has been designed and developed. The amplifier is based on a conventional high electron mobility transistor (HEMT) with 0.25 um gate length. An equivalent circuit model for this device was derived from measuraments up to 18 GHz. The amplifier module has been implemented in a hybrid form on 0.254 mm AI2O3 substrate. A noise figure of 2.9 dB with an associated gain of 6.8 dB (coax to microstrip transitions loss included) have been measured at 35.8 GHz. In-band flatness is better than ± 0.15 dB for noise figure and ± 0.5 dB for associated gain.