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 1 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">st</sup> 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 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">nd</sup> 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 1 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">st</sup> chip was designed using the UMS PH25 process [1] (0.25μm GaAs P-HEMT) whereas the 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">nd</sup> one used the OMMIC ED02AH process (0.2μm GaAs P-HEMT).