Active Phased Array Transmit/Receive Module Enabling Technologies: from GaAs to GaN
Marescialli, L; Bettidi, A; Cetronio, A; Costrini, C; Lanzieri, C; Maccaroni, S; Peroni, M; Romanini, P
SELEX Sistemi Integrati s.p.a.

Phased-array radar systems, based on active electronically scanned antennas (AESA) populated with a high number of Transmit/Receive (T/R) modules are on the cutting edge of advanced radar technology and in the near future will dominate in all application domains (terrestrial, naval, avionic and space).
To be competitive over conventional radars, AESA systems not only need to fulfill the continuous demand for increased performance, but above all must be competitive in terms of reliability and cost. For this reason dominance in T/R module technology, the key enabling technology in AESA systems, is of paramount importance and as such many radar systems companies are developing capabilities to ensure competitive edge products in this field.
From a systemistic point of view the performance of T/R modules can be greatly enhanced by the insertion of the newly emerging wide band-gap semiconductor microwave devices, because of their ability, not only to yield one-order of magnitude higher power density over conventional GaAs-based HEMT, but more important because of their ability to operate at higher efficiency and linearity over large bandwidths and because of their robustness to incident power immunity in front-end receiver applications. In fact with GaN technology, there is a clear opportunity to significantly improve the performance of next generation radar systems.
Because the major impact of GaN technology is foreseen at systems level (by enabling reduced system size and cost, maximizing bandwidth, enhancing detection, guidance and tracking abilities) development of said technology has become an integral part of system development and as such its evolution is strongly governed by a "top-down" approach originating from systems requirements and time to market.
In this presentation the "top-down" approach for GaN HEMT technology development will be presented by illustrating the roadmap and status in harnessing of said technology for next generation radar systems applications. In particular starting form current state-of-the-art GaAs based T/R modules in C and X-band, the advantages of a GaN based Front-End solution will be presented together with the status of specific GaN-HEMT MMIC (HPA, LNA and Switch) development in both coplanar and micro-strip technologies, outlining the issues which still remain for achieving the targeted objective of high performance GaN-based T/R modules.