We report results from a 130nm Indium Phosphide (InP) double heterojunction bipolar transistor (DHBT) technology. A 0.13×2µm<sup>2</sup> transistor exhibits a current gain cutoff frequency ft >520GHz, with a simultaneous extrapolated power gain cutoff frequency f<inf>max</inf>>1.1THz. The HBTs exhibit these RF figures-of-merit while maintaining a common-emitter breakdown voltage BV<inf>CEO</inf>=3.5V (J<inf>E</inf>=10µA/µm<sup>2</sup>). Additionally, scaling of the emitter junction length to 2µm enables high device performance at low total power levels. Transistors in the InGaAs/InP material system have demonstrated the highest reported transistor RF figures-of-merit. Previous published results include strained-InGaAs channel high-electron mobility transistors (HEMTs) with f<inf>max</inf> of >1THz [1,2], and InP DHBTs with f<inf>max</inf> >800GHz [3]. High bandwidth DHBTs have applications in a number of RF and mixed-signal applications due to their high power handling and high levels of integration relative to HEMTs. The HBTs reported in this work are designed for transceiver applications at the lower end of the THz frequency band [0.3–3 THz].