Researchers have realized a fT/fMAX 245GHz/450GHz SiGe:C heterojunction bipolar transistor (HBT) device, a key enabler for future high-volume millimeter-wave low-power circuits to be used in automotive radar applications. These HBT devices also pave the way to silicon-based millimeter wave circuits penetrating the so-called THz gap, enabling enhanced imaging systems for security, medical and scientific applications.