This letter presents a 28–40-GHz 5-bit digital step attenuator (DSA) in a 0.13- $\mu \text{m}$ SiGe BiCMOS technology. The DSA achieves low amplitude and phase variations by using the following techniques: 1) combination of distributed, T-type, and modified $\Pi $ -type attenuators can ensure a low amplitude variation while maintaining a compact size; 2) interstage matching is designed to relax the loading effect between each stage; 3) inductive compensation is adopted to reduce the phase error for 8- and 16-dB attenuation cells. The DSA exhibits a 31-dB tuning range with 1-dB tuning step. The measured rms amplitude and phase errors are < 0.43 dB and < 5.4° over 28–40 GHz, respectively. The insertion loss is 5.4–9.1 dB from 28 to 40 GHz.

中文翻译：

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具有低幅度和相位变化的 28-40GHz 数字步进衰减器

这封信展示了一个 0.13-GHz 的 28-40-GHz 5 位数字步进衰减器 (DSA) $\mu \text{m}$ SiGe BiCMOS 技术。DSA 通过使用以下技术来实现低幅度和相位变化：1) 分布式、T 型和改进型的组合 $\Pi $ 型衰减器可以在保持紧凑尺寸的同时确保低幅度变化；2）级间匹配的目的是放宽各级之间的加载效应；3）采用电感补偿，减少8dB和16dB衰减单元的相位误差。DSA 具有 31-dB 的调谐范围，调谐步长为 1-dB。在 28–40 GHz 范围内，测得的均方根幅度和相位误差分别 < 0.43 dB 和 < 5.4°。从 28 到 40 GHz，插入损耗为 5.4–9.1 dB。