A 20-46 GHz 28nm FD-SOI CMOS Tunable Twisted Hybrid Coupler with Cross-Coupled Capacitor Banks for 5G Applications

A 20-46 GHz quadrature twisted hybrid coupler with a high relative bandwidth of 79 % and low insertion losses is presented in this paper. The hybrid coupler uses an innovative tunable 3-bit architecture with two cross-coupled capacitor banks and offers eight operating modes, enabling it to select the desired center frequency between 22.5 and 43 GHz. The hybrid coupler achieves an insertion loss lower than 1.95 dB with a minimum of 1.05 dB at 22.5 GHz and a phase difference between its two output paths of 91 ± 5°. The circuit is implemented in a CMOS 28nm FD-SOI process and occupies 0.00458 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>.