Design of a 35–95 GHz fundamental monolithic mixer based on a novel IF extraction structure

Abstract

The letter presents a high-performance doubly balanced ring mixer (DBRM) fabricated by a 0.1 µm GaAs pHEMT process that achieves ultrawide radio-frequency (RF) and intermediate frequency (IF) bandwidths. A multiple-coupled-line Marchand balun is optimized to extend the RF bandwidth. A novel structure is designed to directly extract the IF current from the RF balun without an additional IF coupler. Due to the proposed IF extraction structure, the IF bandwidth is broadened with decreased complexity. The size of the whole chip including the probe GSG pads is 0.95 × 0.65 mm². The measured results show that the conversion loss is 7.2–11.9 dB for the RF frequency range of 35–95 GHz with an LO power level of 14 dBm and a fixed IF frequency of 1 GHz. In addition, the conversion loss is better than 12 dB for the IF frequency range from DC to 30 GHz under a fixed LO frequency.