Application of a solid-state ruby maser to an X-band radar system

A solid-state, cavity-type maser has been employed as a pre-amplifier in an X-band radar system. TR leak-through from the transmitted pulse causes the maser to become saturated unless special measures are taken to reduce this leakage. A low-loss, ferrite TR switch that was developed specifically for this purpose provided an additional 30 db of isolation from the transmitted pulse, a value sufficient to allow normal maser operation. With the improved duplexing afforded by the ferrite switch, the measured noise temperature of the maser, circulator, mixer, and i-f amplifier combined was K. The noise temperature of the over-all receiver, including that due to losses in the ferrite switch, the TR tube, waveguide, and rotary joints, was K. The noise temperature of a good X-band radar receiver without a maser preamplifier is to K. The improvement in the detection range obtained by the use of the maser is considered, and the importance of antenna noise temperature is discussed. The feasibility of immediate application in some special radar systems is also considered.