Low Insertion Loss, Compact 4-bit Phase Shifter in 65 nm CMOS for 5G Applications

This letter presents a 28 GHz low insertion loss and compact size 4-bit phase shifter in 65 nm CMOS Technology. In order to get low insertion loss and compact size, this phase shifter is composed of two types of passive phase shifters, high-pass/low-pass type and switched filter type. Various techniques are used such as triple well body-floating, gate-floating, removal of capacitance of the off-state transistor using resonant inductor, and minimized interconnection line which is based on matching network. This phase shifter has 6.36 dB of average insertion loss over the 27.5-28.35 GHz, and loss variation is about 2 dB. The return loss is higher than 12 dB, RMS phase error is 8.98 ^{\circ} , OIP3 is 8.1 dBm at - 10 dBm input power and its core size is 636 \mu m \times 360 \mu m. To the authors' knowledge, these results are the state of the art in CMOS passive phase shifters in K-band frequency.