A 1.5 to 37 GHz ultra-broadband MMIC Mouw´s star mixer

A MMIC ultra-broadband star mixer using Mouw´s hybrid junction is presented in this paper. The MMIC chip uses 0.15μm HEMT process. The chip is measured in three mounting environments, namely, absorber backed, 15mil Al₂O₃ substrate plus absorber, and conductor backed and all of them show ultra-broadband performances. The measured results show that the bandwidth is from 1.5 to 37GHz except a resonant dip near 23 GHz occurs in conductor backed case. The IF 3dB bandwidth is from DC to 2.5GHz. The chip can be used as either up- or down-converter. Because the spiral layout of the Mouw´s hybrid junction shrinks the area significantly, no off chip baluns are required. The chip size is 2mm by 2mm.