A 110-203-GHz 18.3-dBm Broadband Power Amplifier Using Modified Three-Conductor Baluns in 130-nm SiGe BiCMOS

This paper presents a broadband high-power sub-terahertz (sub-THz) power amplifier (PA). By integrating the traditional three-conductor (TC) balun with coupled lines (CP lines), a modified TC balun is proposed for broadband low-loss power combining without significantly increasing the chip area. A pair of these baluns is further connected through a T-junction to form a four-way hybrid power combiner. Based on this combiner, a three-stage four-way PA has been fabricated in a 130-nm SiGe BiCMOS technology. The PA achieves a maximum small-signal gain of 25.2 dB and a 3-dB small-signal bandwidth of 65 GHz from 110 to 175 GHz. It shows a peak saturation output power (Psat) of 18.3 dBm and delivers more than 15.3-dBm Psat from 110 to 203 GHz within a small core area of 0.17 mm2.