A 1-170-GHz Distributed Down-Converter MMIC in a 35-nm Gate-Length InGaAs mHEMT Technology

This paper demonstrates two distributed down-converter monolithic microwave integrated circuits (MMICs). MMIC1 contains a distributed down-conversion mixer and MMIC2 expands MMIC1 by an eight-cell distributed LO driver amplifier. The paper includes an investigation of the optimal gate width for each of the transistors in the stack of the source-feedback mixer cells. The MMICs are fabricated in a 35-nm metamorphic high-electron-mobility transistor technology. MMIC2 achieves a conversion gain (CG) of better than -4.2 dB over a 0-170-GHz radio-frequency bandwidth (BW) at a fixed intermediate frequency of 100 MHz. The LO power (PLO) of MMIC2 is only -1 dBm. Furthermore, the mixer has a variable gain feature. By adjusting PLO, the CG can be controlled without affecting the RF-input-power-related 1-dB CG compression of -1.7 dBm. To the best of the authors' knowledge, this work demonstrates the largest BW for distributed down-conversion mixers and for distributed mixers with a sliding LO.