A 26–44GHz 28nm CMOS FD-SOI Slow-Wave Tunable Hybrid Coupler for 5G Application

This paper presents a 26–44GHz multi-band 90° twisted hybrid coupler exhibiting low insertion loss for 5G application. Using a tunable 3-bit slow-wave architecture, the hybrid coupler offers eight operating modes allowing it to select the desired center frequency and covers a bandwidth of more than 51% while minimizing its losses. The hybrid coupler achieves an insertion loss lower than 2.2dB with a minimum of 1.45dB at 26GHz and a phase shift between the two output paths of 95 ± 5°. The circuit is implemented in a CMOS 28nm FD-SOI process and occupies 0.00567 mm².