Wideband Reconfigurable Power Divider/Combiner in 40-nm CMOS for 5G mmW Beamforming System

A passive and active wideband reconfigurable power divider (PD)/power combiner (PC) is proposed and realized in 40-nm CMOS for fifth-generation (5G) millimeter-wave (mmW) beamforming systems. Based on the conventional Wilkinson PD/PC, the synthesis two-stage LC ladder is used to replace the quarter-wavelength transmission line to save the die area and achieve a wideband design for the passive PD/PC. Besides, the single-pole-double-throw (SPDT) switch function is added to realize the reconfigurable function. In PD mode, the measured | S₂₁| is -4.76/-4.53 dB at 28/38 GHz, and the 3-dB bandwidth (BW) is 22.28 GHz. In switch mode, the measured | S₂₁| is -1.83/-2.10 dB at 28/38 GHz, and the 3-dB BW is 26.93 GHz. Compared with the other reconfigurable PDs/PCs and on-chip PDs, the proposed passive PD/PC demonstrates the widest 3-dB BW and compact area. Besides, we propose an active reconfigurable PD/PC. The bidirectional amplifiers (BDAs), based on modified distributed amplifier (DA) architecture, compensate for the loss of the passive elements. The T-type network inductors, equivalent to magnetically coupled resonator (MCR) circuit, replace the artificial transmission lines to avoid the extra dc dissipation on the termination resistor. By controlling switches, the reconfigurable function and bidirectional mechanism can be implemented. Compared with the other active reconfigurable PDs/PCs, our proposed PD/PC demonstrates a broader BW, lower dc power with a compact die area. IEEE