Silicon germanium (SiGe) heterojunction bipolar transistors (HBTs) combined with optimized passive devices on a CMOS digital platform offer analog and digital functionalities to outperform III-V technologies and standalone CMOS in terms of performance and cost trade-off. Low earth orbit (LEO) satellite and potential D-band (140-160 GHz) 6G applications enabled by SiGe devices are highlighted in this article. A direct conversion D-band transceiver chip set with two double-balanced mixers in the upconverter, a 6x LO frequency multiplier chain in the down converter, and a 32x32 TX and 32x32 RX active phased antenna array system (APAAS) is designed, fabricated and characterized to demonstrate the viability of SiGe technology beyond 100 GHz.