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

Abstract

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 × 0.408 mm (i.e., 0.065 mm2) and achieves S11 smaller than − 10 dB for frequencies of 87.3–101.1 GHz. For frequencies of 94 GHz, the four-way power divider achieves S11 of − 12.2 dB, S21 and S41 of − 8.08 dB, S31 and S51 of − 8.09 dB, and magnitude of amplitude imbalance (MAI) of 0.006 dB and phase difference (PD) of 177° for ports 2–3 and 4–5. For frequencies of 90–100 GHz, the four-way power divider achieves S11 of − 10.5 to − 12.3 dB, S21 and S41 of − 8.09 to − 8.31 dB, S31 and S51 of − 7.9 to − 8.45 dB, and MAI of 0–0.19 dB and PD of 176.8°–178.1° 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.