Wideband Reflection-Type p-i-n Diode Phase Shifters in GaAs MMIC Technology at W-Band

In this paper, we report on developing W-band GaAs $p-i-n$ diode phase shifters (PSs) with a wideband phase and amplitude response. The PSs employ the reflection-type architecture with reflective loads providing discrete phase tunability through diode dc control. We address the design challenge of having a stable phase shift and a minimal insertion loss imbalance for the diodes with a relatively low commutation quality factor at high millimeter-wave frequencies. Two PS examples, namely 180- and 90-degree bits, are designed for the targeted (85-105) GHz operating band. The circuits were fabricated in the commercial PIN-pHEMT GaAs process with $8 \times 8 \mu \mathrm{m}^{2}\,p-i-n$ diodes. Both simulated and measured results are in good agreement demonstrating wideband frequency performance.