Design and Development of HEMT Low Noise Amplifiers in the 40 - 50 GHz band

Two low noise amplifier modules were designed and developed, one based on a conventional HEMT (gate dimension: approximately .25¿m × 100¿m) and one based on a pseudomorphic HEMT (gate dimensions: approximately .15¿m × 50¿m). The devices were modeled for small signal operation and noise perfornance up to 50 GHz. Single stage amplifiers were designed, fabricated and tested using these devices. At 44.5 GHz the conventional HEMT based LNA achieved 5.1 dB gain and 3.5 dB noise figure, whilst the pseudomorphic HEMT based LNA achieved 8.2 dB gain and 3.2 dB noise figure. Comparison between measured results and simulation shows very good agreement over the entire 40-50 GHz band for both modules.