Research Projects

In the past few years, Aluminium Nitride (AlN) based Film Bulk Acoustic Wave Resonators (FBARs) have been extensively studied for the development of miniature chip based RF filters upto X-band. FBAR filters offer a remarkable degree of miniaturization, enhanced performance and extend the frequency of operation from around 2-3 GHz, for Surface Acoustic Wave (SAW) filters, to about 8-10 GHz. This is especially attractive for space applications where size and performance are assigned paramount importance. Besides, the fabrication techniques for FBAR filters are very similar to the processes used in semiconductor manufacturing and hence amenable to monolithic integration. Current trends also point to an increased interest in the development of robust satellite payload systems. A space-based microwave receiver is one sub-system that faces the greatest threat of performance degradation due to intentional or unintentional exposure to high levels of electromagnetic power. Gallium Nitride (GaN) based receiver front ends consisting of GaN HEMT LNAs offers enhanced robustness as compared to existing mainstream GaAs technology, due to its inherent high power capability. The use of GaN LNAs also precludes the use of limiters that provide overdrive protection to GaAs LNAs but at the cost of Noise Figure degradation. Further, integration of the GaN LNA and AlN FBAR filter on the same substrate stack can enable the realization of entire satellite receiver front end on a single chip, thereby offering miniaturization, performance and robustness, all at one go.