Monolithic millimeter-wave distributed amplifiers using AlGaN/GaN HEMTs

Two monolithic broadband distributed amplifiers have been designed and fabricated using AlGaN/GaN HEMTs. One of them uses a standard HEMT for the unit cell and shows a measured S <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</inf> of 5.2±1dB from 1-50GHz. The second distributed amplifier uses dual-gate HEMTs for the unit cell and achieves a measured S <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</inf> of 12±1dB from 2-32GHz. The process consists of 200nm gate-length HEMTs, CPW transmission lines, MIM capacitors and thin-film resistors. The dual-gate distributed amplifier achieves a CW peak output power of 1W and a PAE of about 16% at 4GHz.