Sub-Terahertz Photonic Switched-Beam Antenna with up to 60° Tilt

The rapid expansion of wireless data communication and integrated sensing systems necessitates the development of advanced antenna technologies capable of operating at higher frequencies and bandwidths with dynamic beam management, specifically directional beam control. This paper addresses the challenge by designing a wideband Photonic Switched-Beam Antenna consisting of a 1×4 array of broadband bowtie antenna elements (AEs) fed by PIN photodiodes (PDs) on an InP substrate. Additional semiconductor optical amplifiers (SOAs) enable selective activation of single elements. Beam switching is realized through a hyper-hemispherical lens, where the beam pointing angle is determined by the offset distance of the active AE from the lens axis. Beam pattern measurements confirm clear beam switching behavior with good beam quality up to 300 GHz, and discernible radiation angles up to 2 THz, albeit with degraded beam shapes at the upper end of the spectrum. Our results prove the broadband capabilities of this approach, despite variations in beam quality across different offsets and frequencies. A developed theoretical model, based on subcritical angle incidence at the lens-air interface, accurately predicts the beam pointing angle of the prototype. Simulations have been employed to optimize the design of a 2D antenna array operating at 100 GHz, providing full 3 dB beam coverage within a ±60° range. The presented results highlight the potential of photonic technologies to enable scalable and efficient beam management solutions for applications up to the terahertz frequency range.