Future trends in filter technology for military multifunction systems

This paper assesses and compares state-of-the-art filter technology to the next generation filter technology required for use in military multifunction systems. Military architectures are transitioning from federated systems to wideband multifunction systems which integrate radar, electronic warfare (EW), and communications through a common aperture. This is accomplished while performing in an increasingly dense spectral environment while on increasingly smaller platforms (e.g., small UAV). This evolution hae called for advances in digital beamforming, reconfigurable digital receiver exciters (DREX), wideband phased arrays with lower size, weight, power and cost (SWaP-C). One of the key challenges in next generation DREX architectures is integrating and miniaturizing filters in order to meet the new requirements. Moreover, as DREX moves on-chip and on wafer, filters must integrate at this level to achieve the desired level of miniaturization and channelization required by today´s wide bandwidth complex signal environments. Notable strides have been made across many enabling technologies such as Si/CMOS/SiGe for affordability, GaN for power and linearity, InP HEMT for speed and low noise, MEMS for low loss switching and photonics for high speed distribution. Nonetheless, miniature filter challenges continue to elude full integration on-chip and in 3D wafer level stacks.