A NOVEL THREE VECTOR SUM ACTIVE PHASE SHIFTER DESIGN FOR W-BAND AUTOMOTIVE RADAR APPLICATIONS

摘要

This article presents a novel active W-band phase shifter implemented using IHP SiGe Heterojunction Bipolar Transistor (HBT) 0.25-μm SG25H1 technology with three vector (0°-120°-240°) sum technique. The integrated chip consists of a 3-way Wilkinson power divider/ combiner with 0°-120°-240° phase shifting lines and three low-noise amplifiers (LNA) working at 77 GHz, which comprises a total of 1.5 × 1.1 mm~2 die area. The phase shifting is based on the weighted sum of three vectors which have 120°-angle separation so that all 360° could be scanned with simple amplitude control only. The LNAs are fabricated using IHP technology and can be used successfully in the active phase shifter design. LNA measurement results show that a variable gain of 0-14 dB at 77 GHz can be obtained by sweeping the base voltage between 1.8 and 2.3 V. The simulation results of complete system, including power dividers, phase shifting lines, LNAs, power combiners show that phase can be adjusted by 360° with a maximum gain of 1.8 dB. Input/output return loss for all the possible phase states are below 15 dB. The proposed phase shifter can be used in W-band applications for full scan of 360°.