Compact front-end filter banks for wideband multi-role AESA systems

This paper presents design and measurements of filter banks for T/R-modules in potential wideband multi-role two-dimensional active phased array (AESA) systems. Two different technologies of implementation have been evaluated in this context. Firstly, a multilayer printed circuit boards (PCB) approach; using distributed filters, microstrip and stripline filter, is evaluated in terms of size and performance. Especially, the performance in terms of isolation between adjacent filters has been evaluated. Furthermore, 3D-stacked filter banks are demonstrated, showing a drastic reduction of expended circuit area. Secondly, design and measurements of a 3-channel semi-lumped filter bank in GaAs MMIC is presented, showing the feasibility of an "on-chip" integrated implementation. The study shows that both implementation are compatible, assuming a 10 GHz lattice, for T/R-modules. The MMIC solution offers 50-100 times smaller circuit area, but PCB filters on the other hand offer lower loss and improved selectivity.