A Ka-Band Small-Size Differential Four-Way Wilkinson Power Divider With Multicoupled Inductors

A compact Ka-band differential four-way Wilkinson power divider (WPD) is presented, in which a
$\lambda $
/4 differential transmission line (DTL) is implemented with multicoupled inductors (MCIs). The inductors allow the DTL to be small using the mutual inductances and their interwinding capacitances effectively. The divider implemented in a 28-nm RF CMOS process occupies a compact area of 0.07 mm2. It shows low insertion losses of less than 1.31 dB at 24–30 GHz and less than 1.86 dB at 24–40 GHz. The measured isolation between the output ports is higher than 17.2 dB at 24–40 GHz.