Filtennas for SATCOM Applications: A Performance-Oriented Review

Abstract

Multiple low-earth orbit (LEO) small satellite mega-constellations with advanced, highly integrated payloads are currently being developed to overcome the challenges of beyond-5G satellite communications (SATCOM). To this end, the need to replace traditional radio-frequency (RF) front-end components with alternative compact integrated systems has become evident. Filtennas or filtering antennas can be a promising integrated alternative to conventional satellite antennas (with a cascaded filter in the RF chain) onboard an LEO satellite. Filtennas can minimize out-of-band interference in heavily frequented space-borne traffic while reducing the need for expensive, lossy higher-order filters in the RF front end. Despite their promising characteristics, a comprehensive review is necessary to assess their potential as an alternative to more conventional antenna system solutions. This article examines four of the most technically and practically relevant filtenna configurations. Design guidelines, filtering mechanisms, and key performance indicators are investigated to enable manufacturing reproducibility. The relevant quantitative and qualitative capabilities of filtennas are analyzed in relation to beyond-5G SATCOM requirements. Finally, this article proposes strategies and identifies future research directions to establish filtennas as a viable alternative for beyond-5G SATCOM applications.