The effect of angular dispersion on THz data transmission

Abstract

One of the key distinctions between legacy low-frequency wireless systems and future THz wireless transmissions is that THz links will require high directionality, to overcome the large free-space path loss. Because of this directionality, optical phenomena become increasingly important as design considerations. A key example lies in the strong dependence of angular radiation patterns on the transmission frequency, which is manifested in many different situations including common diffraction patterns and the emission from leaky-wave apertures. As a result of this effect, the spectral bandwidth at a receiver is nonlinearly dependent on the receiver’s angular position and distance from the transmitter. In this work, we explore the implications of this type of effect by incorporating either a diffraction grating or a leaky wave antenna into a communication link. These general considerations will have significant implications for the robustness of data transmissions at high frequencies.

Curving THz wireless data links around obstacles

“…Thus, the generated beam may produce a rainbow-like pattern in free space, where for a given phase distribution , different frequencies follow different trajectories. We emphasize that this phenomenon is distinct from angular dispersion (also known as beam squint 49 ) since it occurs in the near field, and therefore also contains a radial component to the spatial dispersion. This means that the produced rainbow profile can become complicated, and highly depends on the specific caustic trajectory.…”

Conformal leaky-wave antennas for wireless terahertz communications

“…For a planar leaky-wave antenna based on parallel plates, the frequencies peak according to the relation sin ϕ ¼ c=2bf . This angular dispersion can lead to some issues when transmitting large bandwidths since different spectral components will propagate at slightly different angles, thus causing an angular spreading of the information content 57 . This issue becomes more apparent when using a high-gain antenna with an angular narrowing of their main lobe and thus less overlap from the different spectral components.…”

Integrated Communications and Sensing in Terahertz Band: A Propagation Channel Perspective

“…Although some of the additional available channel features are therefore lost, with fewer multipath components THz sensing and localization systems can achieve higher spatial resolution. Moreover, due to the beamforming, the THz channels are extremely sparse in the angular domain, and the number of resolvable angular paths of THz radio waves is significantly limited compared to lower frequency channels [58], [43].…”