Design and analysis of four-way power divider for 94 GHz power amplifiers in 90 nm CMOS process

A millimeter-wave miniature CMOS dual-balun-based four-way power divider is reported. The four-way 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. In contrast to the traditional four-way PA that uses three two-way Wilkinson power dividers for four-way power dividing, the proposed PA architecture achieves smaller chip area, and higher output power and power-added-efficiency. The four-way power divider occupies a small chip area of 0.16 mm x 0.408 mm (i.e., 0.065 mm(2)) and achieves S-11 smaller than - 10 dB for frequencies of 87.3-101.1 GHz. For frequencies of 94 GHz, the four-way power divider achieves S-11 of - 12.2 dB, S-21 and S-41 of - 8.08 dB, S-31 and S-51 of - 8.09 dB, and magnitude of amplitude imbalance (MAI) of 0.006 dB and phase difference (PD) of 177A degrees for ports 2-3 and 4-5. For frequencies of 90-100 GHz, the four-way power divider achieves S-11 of - 10.5 to - 12.3 dB, S-21 and S-41 of - 8.09 to - 8.31 dB, S-31 and S-51 of - 7.9 to - 8.45 dB, and MAI of 0-0.19 dB and PD of 176.8A degrees-178.1A degrees for ports 2-3 and 4-5. The state-of-the-art results of the proposed four-way power divider indicate that it is suitable for 94 GHz image radar sensors.