From the Editors of the Special Issue on Multiplatform and Multifunctional RF Systems

The idea for this Special Issue on Multiplatform and Multifunctional RF Systems [(MPRFS) and (MFRFS)] was conceived in 2020 on the strength of a very successful workshop on Multiplatform RF Systems organized by the European Defence Agency (EDA). The editors were further motivated by the realization that modern platforms such as fighter jets, drones, reconnaissance aircraft, frigates, destroyers, and submarines have limited real estate for the inclusion of even more sensors—giving rise to the field of MFRFS. MFRFS represents a research and technology endeavor to realize multiple RF functions such as radar, electronic attack (EA), electronic support (ES), and communications (Comms) in a platform– sensor suite through the sharing of hardware architectures. There is no standard definition for MFRFS, but one interpretation is the use of active electronically scanned array (AESA) antennas for radar, EA, ES, and Comms so that the overall number of antennas distributed over a given platform may be reduced. There are, of course, other valid interpretations not predicated on the use of ASEAs, but rather aim to consolidate multiple functions into one suite of common hardware. The concept of MPRFS is based on the controlled utilization of RF systems that are available within an interconnected and spatially dislocated multiplatform constellation. Individual platforms may be strategically positioned and managed to improve constellation performance in complex operational environments. MPRFS and MFRFS are areas of active research and this is set to intensify in the coming years. We, as guest editors, are pleased to publish this first special issue dedicated to the field of MPRFS and MFRFS and, as the field matures, we are confident that future special issues will follow. This special issue comprises four interesting contributions. Each is briefly summarized.