A 90-100 GHz SiGe BiCMOS 6-Bit Digital Phase Shifter with a Coupler-Based 180° Unit for Phased Arrays

Area of Science:

• Electrical Engineering
• Microwave Engineering
• Semiconductor Device Physics

Background:

• Digital phase shifters are crucial components in modern radar and communication systems.
• Achieving wideband operation with fine phase resolution at millimeter-wave frequencies presents significant design challenges.

Purpose of the Study:

• To present a novel wideband digital phase shifter operating from 90-100 GHz.
• To achieve full 0-360° phase coverage with high accuracy and improved bandwidth.
• To demonstrate a compact and robust design suitable for phased-array applications.

Main Methods:

• Implementation of a switch-type architecture with six cascaded units.
• Inclusion of a novel 180° phase shift cell utilizing a broadband coupler.
• Design and simulation using a 0.13 μm Silicon-Germanium (SiGe) BiCMOS process.

Main Results:

• Achieved full 0-360° phase coverage with a fine resolution of 5.625°.
• Demonstrated insertion loss below 15.5 dB across the 90-100 GHz band.
• Exhibited root-mean-square (RMS) phase error under 2.3° and RMS amplitude error better than 0.9 dB.

Conclusions:

• The developed digital phase shifter offers excellent performance metrics including accuracy, bandwidth, and phase coverage.
• The compact chip area (0.39 mm²) makes it suitable for high-density integration in phased-array systems.
• The SiGe BiCMOS implementation ensures process robustness and high-frequency performance.