Abstract

The design and performance of a low power GaAs multi-function X-band MMIC for space-based synthetic aperture radar (SAR) application with 7 bit phase and amplitude control, is described. The multi-function chip (MFC) consists of switches for selection of the transmit or receive mode, a 7-bit phase shifter, a 7-bit attenuator and several amplifiers. The MFC frequency range is 9 to 11 GHz for both transmit and receive. The phase setting of the MFC is from 0° to 360° with an accuracy better than ± 3°. The gain setting range is more than 20dB with an accuracy smaller than ± 0.21 dB. The input and output return losses are better than 14 dB for all ports. The gain for transmit and receive is 3 dB. The noise figure for the receive chain is better than 4.5 dB with a third order intercept point of 13.5 dBm. The P-ldB compression point of the transmit chain is better than 14 dBm. The bias supply voltages are +5 and -5 Volts. The total power consumption of the chip is about 0.3 Watt regardless of the transmit or receive mode. The size of the MFC is 4.2 x 4.2 mm2. The integration of functions combined with the low power consumption and the excellent specifications, are making this multi-function chip extremely suitable for future high performance space-based synthetic aperture and phased-array radars.