CMOS RF active inductor with improved tuning capability

This paper presents an improved low power CMOS active inductor topology suitable for RF filtering. The circuit is derived from a previous designed transistor-only active inductor by adding a floating voltage source to one transistor gate fact that positively changes the overall dc biasing. If a current source with high output resistance is used for active inductor, this method can lead to lower interdependence between the self resonant frequency and quality factor. The simulations were carried out in 0.18 mum CMOS technology.