HIGH SPEED SIGE MMICS FOR PHASED ARRAY COMMUNICATIONS By

by Pinping Sun, Ph.D. Washington State University August 2008 Chair: High speed SiGe MMICS for phased array communications has been widely used in satellite communications. This dissertation presents the development of reconfigurable SiGe MMICs for upper X-band or lower Ku band satellite phased array communications. Novel high-isolation, low-insertion-loss and highly linear octagonal PIN diode has been designed on SiGe substrate to improve on the current state of the art performance. Fabricated in a standard 0.18-μm SiGe BiCMOS technology, the 50 μm 2 PIN SPST switch can achieve an insertion loss of less than 0.65 dB from 2 to 18 GHz with the measured P1dB of 16 dBm. The radiation tolerance of the developed PIN diodes has been verified with TID test up to 1000 krad. Based on the novel PIN diode implementation, the new SPDT architecture which alleviates the leakage caused by the Psub-Nwell parasitic diodes has been presented. The measurement results shows that the SPDT switch can achieve a through-path loss of 1.2 to 1.8 dB and an isolation path loss of 51 to 36 dB over a wide frequency range (2 to 18 GHz). A 4-bit Ku-band bridged-T filter type PIN diode phase shifter is used to realize 0 0 to 360 0 phases with a resolution of 22.5 0 . The average power consumption of this phase shifter is only 2.5 mA with a 3.3 V voltage supply. This phase shifter achieves compact chip area, flat phase response, low delta insertion loss, high return loss and low power consumption. The low power active combiner is used to combine the multiple phase shifters into a phased array.