A K-Band Compact Power Divider/Combiner With 50-dB Configurable Isolation in 65-nm CMOS

This letter presents a K-band compact Wilkinson power divider/combiner (WPDC) with 50-dB configurable isolation in 65-nm CMOS. The WPDC is implemented by LC-based spiral transmission lines (LCSTLs), switched capacitors, and a DAC with a core area of 0.09 mm². The measured insertion loss was 2.5 dB with 0.2 dB fluctuation in the passband. The measured amplitude and phase error are within 0.2 dB and 0.7° from dc to 50 GHz, respectively. The proposed WPDC supports four operation modes, in which the isolation of more than 35 dB from 20.2 to 27 GHz can be maintained with a peak isolation of 60 dB (@ 22.4 GHz). To the best of our knowledge, the WPDC is the only millimeter-wave power divider/combiner (PD/C) that can achieve an isolation of more than 35 dB within a 29% relative bandwidth in CMOS process.