A 250 kW solid-state AN/SPS-40 radar transmitter

The solid-state transmitter design meets or exceeds all the performance criteria of the existing tube transmitter and also offers many new capabilities. The most important of these is a mean-time-between-failure of 10,000 hours. The transmitter has a single output port, rather than an active phased array transmitter, and operates under the existing radar pulse width and duty conditions, as a minimum. A key feature of the transmitter is the high degree of modularity: the 128 amplifier modules comprise only two types, and there are 12 identical power supplies. The nominal 250-kW output of the transmitter is attained by the parallel combination of 112 transmitter modules located in the output stage of the transmitter. Each of these modules has a nominal output power of 2500 watts. Detailed descriptions are given of the transmitter architecture, the transmitter power modules, and the power combiners. A table giving the key specifications of the solid-state transmitter is included, showing a frequency of 400 to 450 MHz, an instantaneous bandwidth of 50 MHz, a bandpass flatness of + or - 0.5 dB maximum, and a gain of 66 dB minimum.