A miniaturized wilkinson power divider with CMOS active inductors

A miniaturized Wilkinson power divider implemented in a standard 0.18-μm CMOS process is presented in this letter. By using active inductors for the circuit implementation, a significant area reduction can be achieved due to the absence of distributed components and spiral inductors. The power divider is designed at a center frequency of 4.5 GHz for equal power dividing with all ports matched to 50 Ω. Drawing a dc current of 9.3 mA from a 1.8-V supply voltage, the fabricated circuit exhibits an insertion loss less than 0.16 dB and a return loss better than 30 dB at the center frequency while maintaining good isolation between the output ports. The active area of the miniaturized Wilkinson power divider is 150 × 100 μm ², which is suitable for system integration in monolithic microwave integrated circuit (MMIC) applications.