Design of Ka-Band Reflection-Type Phase Shifter Using Offset Broadside-Coupled Line Coupler in 0.13 µm SiGe BiCMOS Technology

Abstract

A 36 - 38 GHz Ka-band SiGe BiCMOS reflection-type phase shifter (RTPS) for a soil moisture radiometer antenna is presented. The phase shifter comprises an offset broadside-coupled line 3 dB coupler and two identical varactor reflective loads for continuous phase shift. The offset broadside-coupled line coupler is designed to achieve smaller insertion loss (IL) compared to a normal broadside coupled line coupler. The varactors, which are essential components of the reflective loads, are biased with a variable voltage from -1 to 2 V to control phase shift continuously. The simulation results show that the phase shifter yields a phase shift from 0° to 253° with 12 ± 2 dB IL. More than 12 dB about the input and output return loss (RL) is obtained over 36 - 38 GHz. The phase shifter is designed using 0.13 μm SiGe BiCMOS technology. The chip consumes almost zero DC power. The chip is compact, with the core area of about 0.32 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .