Monolithic active filters at microwave frequencies

The authors describe the properties of a class of active RF filter circuits designed on a Silicon on Insulator (SOI) bipolar IC process. Simulations have been carried out at frequencies from 10 MHz to 1.6 GHz. Q values from 4 to over 100 are possible, without the use of inductors. The application for these circuits is in low power radio communications. Measured results on trial circuits confirm the simulations, both in respect of the filter capabilities and the other issues important in communications applications, i.e. noise performance and signal handling capability.