A 94 GHz flip-chip packaged SiGe BiCMOS LNA on an LCP substrate

In this paper, the authors present for the first time a 94 GHz flip-chip packaged SiGe BiCMOS LNA on a liquid-crystal-polymer (LCP) substrate. The LNA is a custom design in a 0.13 μm SiGe BiCMOS process, and features a four stage common-emitter topology. The measured on-wafer gain equals 17.2 dB and the noise figure is below 7 dB at 94 GHz with a 3dB bandwidth of 18 GHz and a power consumption of 24 mW. For the packaging, the flip-chip technique is utilized on a flexible, light-weight LCP substrate material. Measured results show that the packaged LNA provides 15.9 dB gain (at the same power consumption), only 1.3 dB lower than the on-wafer case. These results demonstrate the suitability of the LCP as a substrate material, and the low-loss potential of the flip-chip packaging technique for millimeter-wave applications.