Miniaturized 3-bit Phase Shifter for 60 GHz Phased-Array in 65 nm CMOS Technology

The letter presents a compact 3-bit 90
$^{\circ}$
phase shifter for phased-array applications at the 60 GHz ISM band (IEEE 802.11ad standard). The designed phase shifter is based on reflective-type topology using the proposed reflective loads with binary-weighted digitally-controlled varactor arrays and the transformer-type directional coupler. The measured eight output states of the implemented phase shifter in 65 nm CMOS technology, exhibit phase-resolution of 11.25
$^{\circ}$
with an RMS phase error of 5.2
$^{\circ}$
. The insertion loss is 5.69
$\pm$
1.22 dB at 60 GHz and the return loss is better than 12 dB over 54–66 GHz. The chip demonstrates a compact size of only 0.034
${\rm mm}^{2}$
.