Abstract
An ultra-wideband four-stage 220GHz amplifier in a 0.13- \mu m SiGe BiCMOS technology is proposed in this letter. The cascode topology is deployed as a unit amplifier to provide sufficient power gain. To broaden the bandwidth, the staggered-tuning model for the cascode amplifier is studied, analyzed, and applied in the amplifier design. The fabricated circuit achieves a peak gain of 15.5 dB at 210GHz, a 3-dB bandwidth of 47GHz, an output P_{\text {1 dB}} of −9.7 dBm at 220GHz. The amplifier occupies a compact area of 0.154 mm 2 . The dc power consumption is 20.4mW at 2.4 V supply voltage.