The design of a broadband on-chip antenna for passive THz imaging in the frequency range of 0.6 THz to 1.4 THz is reported. The antenna design has to fulfill the requirements of the IBM CMOS process and the MEMS post CMOS processing. The antenna is coupled directly to the sensor, a MOSFET bolometer. Because of this direct coupling and the need for real time imaging, only extremely physically small antennas are feasible. Hence, typical broadband antennas like the toothed log-periodic antenna are not useable for this application and new antenna approaches have to be examined. © 2013 IEEE.