Novel MMIC architectures for tunable microwave wideband active filters

Abstract : This paper reports on two novel architectures for designing tunable microwave active bandpass filters in MMIC technology. The 1st MMIC concerns a frequency-tunable active bandpass filter based on the principle of "actively-coupled passive resonators". Starting from a specific synthesis method developed for fixed-frequency high-order filters, the frequency tuning ability is now performed by the use of varactor-diodes. This new feature is illustrated by the design of a tunable 3-pole active bandpass filter centered at 12 GHz on GaAs. The 2nd MMIC implements a frequency-selective wideband active bandpass filter with the ability to select the required band. This feature is achieved by the use of a channelized configuration. To demonstrate this ability, a GaAs chip has been designed using 3 active filtering channels, embedded in a distributed topology to perform a 3-pole bandpass response in the [9-15] GHz range. The 1st chip was designed using the UMS PH25 process [1] (0.25μm GaAs P-HEMT) whereas the 2nd one used the OMMIC ED02AH process (0.2μm GaAs P-HEMT).