X-band cascode LNA with bias-invariant noise figure using 0.15 µm GaN-on-SiC technology

Cascode HEMTs exhibit better stability and broad bandwidths performance as compared with common source HEMTs. This paper presents the design of a single stage broadband low noise amplifier based upon 0.15 um GaN HEMT technology in the frequency range of 8 – 12 GHz. Cascode HEMT with inductive source degeneration is utilized. All the design work is done using PathWave Advanced Design System. The LNA provides 9.5 to 10.6 dB with input return loss better than 10 dB and output return loss better than 8 dB in the whole band. The noise figure of the amplifier is below 1.9 dB. The linearity parameters P1dB and OIP3 are greater than equal to 16 dBm and 28 dBm respectively within operating bandwidth. The noise figure of the amplifier is fairly constant over 30 mA to 60 mA bias currents and 9 V – 18 V operating bias voltage. This is a unique finding which is being reported for the first time to the best of authors' knowledge.