9350206 Popovic The research concentrates on quasi optical power combining of microwave and millimeter wave solid state devices. This technique allows the powers of a large number of individual devices to be combined in a compact, low cost, reliable high power source. Since the power combining occurs in free space, radiation and antenna design are addressed. Both amplifier and oscillator combiners are studied, using FETs or bipolar transistors. A design oriented analysis is developed for optimizing the radiating structure geometry towards different design criteria, such as power, bandwidth, efficiency or low noise. In the case of oscillators, nonlinear behaviour and injection locking of a large number of devices are studied. In the case of amplifiers, a high efficiency circuit topology is combined with the radiating structure in order to minimize heat sinking requirements. The goal of the work is to develop a compact, inexpensive microwave solid state source for a variety of applications, such as vehicular radar, mobile communications, wireless communications, atmospheric studies and remote sensing. ***
