Delay control in wide band Front-End components for multi-role/multi-domain phased-array systems

In the framework of a bilateral Research Programme between Italy and Sweden MoDs (M-AESA), one of the main objective was the feasibility in terms of design dominance of analog Time Delay control in AESA Front-End. The need of managing the antenna beam-steering in terms of Time Delay, instead of phase-shifting, is due to the necessity of wide Instantaneous Bandwidth Requirement at System level. In this paper a solution which foresees the integration of the needed time delay both inside the TRMs and inside the RF Beam Forming Network is presented. In particular the feasibility evaluation has been performed by including smaller bits for Time Delay control in a GaAs chip (Core Chip) within the wide band TRM, to allow the amplitude and Delay control on each radiating element of the active antenna. As regards the higher bits, they have been included in a single True Time Delay component suitable for analog beam-forming network applications at sub-array/antenna level. It is worth to underline the added value of the solution directly applied on wide band components. The last, but not the least, challenging requirement was the size constraints, due to the X-Band array lattice. To do this, standard technologies for the integration solution (LTCC) and also for the chipset (pHEMT GaAs) at TRM and TTD level have been used. The high integration solutions for TRM and TTD component, the obtained performances, their compliance with design expectations shall be presented.