A Compact 75--105 GHz Symmetric-Cell-Based Distributed Attenuator With Broadband Phase Compensation

Abstract

This letter introduces a compact distributed attenuator with low phase error, employing a novel second-order phase correction (SOPC) technique. In each attenuation unit, two switch transistors are symmetrically distributed at both ends of the transmission line to form a second-order network, effectively compensating phase deviations without extra area overhead. The analysis and design of the attenuator are described. The proposed 5-bit attenuator is fabricated in a 130-nm SiGe BiCMOS process. Measurement results demonstrate that over 75–105 GHz, the attenuator achieves an insertion loss of 3.1–4.6 dB and a 12.8 dB tuning range with 0.4 dB step size. The rms phase error is <2°>2.