A Linear GaN High Power Amplifier MMIC for <roman>Ka</roman>-Band Satellite Communications

Abstract

A linear high power amplifier (HPA) monolithic microwave integrated circuit (MMIC) is designed with 0.15 μm gallium nitride (GaN) high electron mobility transistor (HEMT) technology on silicon carbide (SiC) substrate. To keep the linear characteristics of the power stage, 2:4:8 staging ratio of 8 × 50 μm unit transistor is adapted for the 3-stage HPA MMIC. The MMIC delivers P3 dB of 39.5 dBm with a PAE of 35% at 21.5 GHz. Linear output power (P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> ) meeting IMD3 of -25 dBc is 37.3 dBm with an associated PAE of 29.5%. The MMIC dimensions are 3.4 mm × 2.5 mm, generating an output power density of 1049 mW/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .