An Ultra-Compact Folded Inductor Based Wideband Gysel Power Divider for Multi-Band 5G Applications

This paper presents a folded inductor based Gysel power divider with ultra-compact form factor, wide bandwidth, and low loss for multi-band 5G applications. The instantaneous bandwidth as defined by |S21| 3-dB bandwidth is 81.6% over 22.1 GHz – 52.6 GHz, and the insertion loss (IL) is 0.81 dB. The return loss |S11| (RL) is below -10 dB over 22.8 GHz – 49.3 GHz (73.5% fractional bandwidth). The amplitude mismatch is < 1.03 dB over both specified bandwidths, and the measured phase mismatch is < 8.4°. The isolation is below -9.97 dB over the entire operation bandwidth and below -15 dB over 26.9–47.2 GHz. The Gysel power divider is implemented in a 45nm CMOS SOI process, and its normalized form factor, defined as the core size divided by the wavelength at the center frequency, is ultra-compact (0.0336 × 0.0574). The divider proves competitive among all reported designs.