CMOS Four-Way Power Divider for W-Band Power Amplifiers

Abstract

A W-band CMOS dual-balun-based four-way power divider is reported. The power divider can be applied to a four-way power amplifier (PA) for four-way power dividing or a star mixer for converting the single RF (or LO) input signal to dual differential RF (or LO) signals. The power divider occupies a small chip area of 0.065 mm2 and achieves S 11 smaller than -10 dB for frequencies of $87.3 \sim101.1$ GHz. For frequencies of $90 \sim100$ GHz, the power divider achieves S 11 of - ${10.5 \sim}$ -12.3 dB, S 21 and S 41 of - ${8.09 \sim} -$8.31 dB, S 31 and S 51 of - ${7.9 \sim} -$8.45 dB, and amplitude imbalance magnitude (AIM) of $0 \sim0.19$ dB and phase difference (PD) of 176.8° ${\sim178.1} ^{o}$ for ports $2 \sim3$ and $4 \sim5.$ Moreover, the proposed four-way PA achieves output power (P out ) of 15.2 dBm and power-added-efficiency (PAE) of 16.8 dBm at 94 GHz, better than those (P out ) of 12.1 dBm and PAE of 7.7% at 94 GHz) of the traditional four-way PA that uses three Wilkinson power dividers for four-way power dividing. The prominent results of the PA indicate that the power divider is suitable for W-band PAs and star mixers.