A wideband accurate compact 6‐bit phase shifter in 0.15‐μm GaAs technology

Abstract

AbstractA Ku wideband accurate compact 6‐bit digital phase shifter is designed in this letter using three different switched phase shift structures: the switched L/C structure, T‐type structure, and high‐pass/low‐pass network. To improve the bandwidth and the gain flatness, an improved switched L/C structure is used and the systematic cascade sequence of the phase shifter is optimized. The improved switched L/C structure solves the problem that conventional L/C networks are hypersensitive to the coupling capacitance at high‐frequency input. As a result, the improved L/C structure can achieve wideband and better s‐parameters. The proposed 6‐bit switched phase shifter is implemented in 0.15‐μm GaAs pHEMT process. The measured root‐mean‐square (rms) phase error is less than 2.8° at 12–18 GHz, and the average insertion loss (IL) is 6.5–6.9 dB. The chip size of the proposed 6‐bit digital phase shifter is 3.1 × 1 mm2, including all RF and dc pads, which is very suitable for radar systems.