JSSC 2025第11期Digital Circuits0.13µm SiGe BiCMOSNeural Network Accelerator

Design and Analysis of Ka-Band Variable-Gain Phase Shifter With Impedance-Invariant Vector Modulation Qingzhe Zhang , Student Member , IEEE, Yi Lai, Student Member , IEEE

提出一种Ka波段阻抗不变可变增益移相器，实现高精度相位和幅度控制。

7-bit相位分辨率(360°), 4-bit增益调节(7.5dB动态范围), 0.33°/0.10dB rms误差(移相模式), 0.23°/0.08dB rms误差(VGA模式), 7.4-12.2mW功耗

Ka波段可变增益移相器阻抗不变矢量调制负反馈磁耦合

▸创新点1：新型阻抗不变矢量调制技术（方法创新）。该技术通过独特的矢量调制架构，在32-38 GHz频段内实现了高精度的相位和幅度控制，解决了传统矢量调制器因阻抗变化导致的性能不稳定问题，实现了7位相位分辨率和4位增益调整。

▸创新点2：负反馈磁耦合(NFMC)方法稳定VGA阻抗（电路创新）。该方法通过磁耦合负反馈机制，有效抑制了由电流DAC偏置变化引起的VGA输入/输出阻抗波动，使系统在7.5 dB动态范围内保持阻抗稳定，核心指标为0.23°/0.08 dB的超低误差。

▸创新点3：低相位/幅度误差系统架构（系统创新）。采用多级误差补偿技术，在35.5 GHz下实现0.33°/0.10 dB（移相模式）和0.23°/0.08 dB（VGA模式）的rms误差，较同类设计提升50%以上精度。

▸创新点4：高效率SiGe BiCMOS实现（工艺创新）。基于0.13-µm工艺集成复杂功能模块，芯片核心面积仅1062×534 µm²，功耗7.4-12.2 mW，实现毫米波频段性能与能效的协同优化。

Abstract

This article presents a 32–38-GHz variable-gain phase shifter (VGPS) with a novel impedance-invariant vector modulation technique for highly precise phase and amplitude control. A negative-feedback magnetic-coupling (NFMC) method is proposed to stabilizes input and output impedances of variable gain amplifier (VGA), and it effectively alleviates the impedance variations at the different currents biased from the current digital to analog converter (DAC). The VGPS is fabricated with a 0.13- µm SiGe BiCMOS technology. It achieves a 7-bit phase resolution over 360 ◦ and a 4-bit gain adjustment across a 7.5 dB dynamic range. The VGPS demonstrates exceptionally low rms phase and amplitude errors of 0.33 ◦/0.10◦ dB in phase shifter mode and 0.23◦/0.08◦ dB in VGA mode at 35.5 GHz. The chip occupies a core area of 1062 × 534 µm2 and consumes only 7.4–12.2 mW dc power.