A Compact Ka-Band Hybrid Analog/Digital Phase Shifter With GaAs Technology

This paper proposes a Ka-band hybrid analog/digital phase shifter based on 0.15 μm GaAs pHEMT technology for 5G millimeter-wave applications. The phase shifter adopts the combination design of 3-bit digital and one analog phase-shifting cells to take the advantages of both types. The 180∘, 90∘ and 45∘ digital phase shifting cells are realized by balun-based, reflective-and embedded-type structures, respectively, for broadband and small amplitude variation. A reflective-type analog 45∘ cell is used to compensate for the phase errors of digital cells by the continuous variable capacitance of the Schottky diodes, with small size and insertion loss. The hybrid phase shifter takes an area of less than 2 mm2 with 6-bit precision, the rms phase error less than 2.6∘, the rms amplitude error less than 0.5 dB, and the insertion loss of 6.6∼9.3 dB.