Two-level power combining using a lens amplifier

A two-level quasi-optical power combiner is presented. The combiner consists of a grid oscillator which feeds a transmission amplifier at its focal point. The focal-point feed improves power coupling efficiency over that of a plane-wave feed. A linear 7-element lens amplifier array demonstrates 29 dB of isolation and a 30/spl deg/ continuous scan angle with less than 1 dB power variation at 9.7 GHz. A 23-element two-dimensional lens amplifier array fed by a grid oscillator demonstrates 5.7 dB gain and a 30/spl deg/ scan angle with less than 2 dB power variation at 10.25 GHz. When horn-fed, the 24-element lens has an isolation of 17-21 dB over a 3% bandwidth. The grid oscillator, as well as receive and transmit sections of the lens amplifiers, are each fabricated on single substrates, making monolithic millimeter-wave integration of each component possible.