Very large, lightweight phased array antenna apertures are highly desirable for space-based ground surveillance and tracking radars since power is limited by the mass efficiency of solar power collection and distribution systems which compete for the limited payload capability of the launch vehicle. This leads to relatively low power density apertures whose power budget can be dominated by the overhead (non-radiated) power used during the receive portion of the radar timeline. We have developed a novel lens antenna concept to meet the extreme demands of next-generation, large-aperture space-based radar with significantly improved electrical and mechanical efficiency. The agile beam design offers better aperture efficiency over the entire field of regard compared with reflector designs and better electrical and mass efficiency than active array designs. The lens contains embedded MMIC modules that have been optimized for low power consumption on receive a significant departure from T/R modules used in airborne radar applications.

Abstract?The choice of InP HEMT technology is discussed for a highly efficient integrated T/R module. The module includes a receive path comprising of a low noise amplifier, phase shifter and amplifier consuming only 5mW of DC power at X-band. The transmit path combines phase shifters and amplifiers to provide 10mW of power per module at an efficiency of 50%. This is achieved by increasing the Cut-off frequency of InP HEMT devices and sacrificing their gain for lower DC power consumption. This provides both DC and PF performance criteria for the space based radar antenna design requirements. Future T/R module technologies are also discussed based on the Antimonide based material system which have already shown a factor of 3-4 reduction in DC power consumption compared to InP HEMT technology.