Low-current design of gaas active inductor for active filters applications

Active inductors are suitable for MMIC integration, especially for filters applications, and the definition of strategies for an efficient design of these circuits is becoming mandatory. In this work we present design considerations for the reduction of DC current in the case of an active filter design based on the use of active inductors and for high-power handling. As an example of applications, the approach is demonstrated on a two-cell, integrated active filter realized with p-HEMT technology. The filter design is based on high-Q active inductors, whose equivalent inductance and resistance can be tuned by means of varactors. The prototype was realized and tested. It operates between 1800 and 2100 MHz with a 3 dB bandwidth of 30 MHz and a rejection ratio of 30 dB at 30 MHz from the center frequency. This solution allows to obtain a P1 dB compression point of about −8 dBm and a dynamic range of 75 dB considering a bias current of 15 mA per stage.