High quality factor integrable bandpass filter by using tunable active inductor

In this paper the design of a fully-integrable inductorless high quality factor active inductor (AI) based RF bandpass filter is presented. The AI includes a passive variable phase- and amplitude-compensating network and a highly linear inverting amplifier, forming a gyrator-C architecture. The equivalent inductance and resistance values are tuneable in a wide frequency range; outside the operating frequency band, the inductor equivalent resistance increases, improving signal rejection for band-pass filter applications. The filter, implemented in a first step as a discrete element board with commercial components in order to show the design feasibility, operates at a 3.3V with a power consumption of about 100mW. It can be tuned in the range 1.8GHz to 2GHz center frequency, and has a quite constant band-quality factor of greater than 200 with a 12-dB noise figure.