SiGe BiCMOS ICs for an X-Band 7-Bit T/R Module with High Precision Amplitude and Phase Control
Electronics Engineering, M.Sc. Thesis Dissertation, 2015
Prof. Dr. Yaşar Gürbüz (Thesis Advisor), Assoc. Prof. Dr. Meriç Özcan
, Assoc. Prof. Dr. Feysel Yalçın Yamaner
Date & Time: August 3rd, 2015 – 11:00 AM
Place: FENS G035
Keywords : Phased Array Radar, T/R Module, SiGe BiCMOS, Attenuator, SPDT switch,
Low Noise Amplifier
Over the last few decades, phased array radar systems had been utilizing transmit/receive (T/R) modules implemented in III-V semiconductor based technologies. However, their high cost, size, weight and low integration capability created a demand for alternative solutions. In recent years, SiGe BiCMOS technologies are rapidly growing their popularity in T/R module applications by courtesy of meeting high performance requirements with more reduced cost and power dissipation with respect to III-V technologies. The next generation phased array radar systems require a great number of fully integrated, high yield, small-scale and high accuracy T/R modules. In line with these trends, this thesis presents the design and implementation of a novel 7-Bit X-Band T/R module with high precision amplitude and phase control, which is realized in IHP 0.25μ SiGe BiCMOS technology.
In this thesis, the design of the T/R module sub-blocks such as a highly linear low noise amplifier (LNA), wideband inter-stage amplifier, SiGe hetero-junction bipolar transistor (HBT) single-pole double-throw (SPDT) switch with high isolation and low insertion loss (IL) are demonstrated. Moreover, a low phase/amplitude error 7-Bit digitally controlled step attenuator utilizing iNMOS for lower IL is discussed. The 7-Bit T/R module is constructed by using the sub-blocks aforementioned, along with a 7-Bit vector sum phase shifter and a 2-stage cascode power amplifier. Post-layout simulation results show that the designed T/R module exhibits a substantial gain of 38dB, relatively low RMS phase error of 2.6°, extremely low RMS amplitude error of 0.82 dB and Rx-Tx isolation of 80 dB across X-Band frequencies. The layout of the T/R module occupies an area of 11.37 mm2. The designed 7-Bit T/R module enables performance enhancement of phased array radars in terms of low sidelobe level, high directivitiy, more beam sharpness and sensitivity.