This paper presents a 190-GHz direct-conversion receiver capable of supporting higher order modulation schemes and implemented in a 130-nm SiGe BiCMOS technology. The circuit consists of a low-noise amplifier, an active fundamental mixer, a local-oscillator driver, a variable-gain baseband (BB) amplifier, and a totem-pole output stage. To exploit the advantages of sub-THz frequencies in terms of available bandwidth (BW) at a low dc power consumption, all circuit blocks are concurrently optimized for large BW and high power efficiency. A high and tunable conversion gain as well as a large maximum BB voltage swing is targeted to allow direct operation with state-of-the-art analog-to-digital converters. While consuming only 122 mW of dc power, the fabricated circuit exhibits a record 3-dB RF BW of 35 GHz, a maximum conversion gain of 47 dB with a tuning range of 20 dB, a maximum BB voltage swing of more than 800 $\text {mV}_{\mathrm{ pp}}$ , and a minimum double-sideband noise figure of 10.7 dB.