High-efficiency L-band transmit/receive module for synthetic aperture radar

Space-based radar places significant demands on the spacecraft resources (mass, power, data rate) and is therefore very expensive to implement. These systems typically require active phased-array antennas with hundreds or thousands of transmit/receive (T/R) modules distributed on the array. High-efficiency is a vitally important figure of merit for the radar T/R module because it reduces the power consumption and therefore makes best possible use of the limited power available. High efficiency also improves the thermal design and reliability. In this paper, we describe the design and preliminary results of a novel L-band (1250 MHz) T/R module technology to achieve ultra-high efficiencies. We will show that a dramatic improvement in overall T/R module efficiency is possible using high-efficiency class-E/F amplifiers. The T/R module performance goals are to achieve an overall module efficiency greater than 70% with a minimum of 30-W output power at L-band frequencies.