Efficient leaky-wave antennas at terahertz frequencies generating highly directional beams

Abstract

Due to their frequency-dependent angular emission, leaky-wave antennas have been recently introduced in the terahertz band to tackle many of the challenges associated with THz wireless communications. Most previous works have exploited conventional leaky-wave waveguide architectures developed for the microwave region. In this paper, we study in detail the emission characteristics of leaky-wave antennas at THz frequencies. We show that, at these high frequencies, the wavelength-scale interaction with the aperture causes a nonuniform electric field distribution at the slot interface, which is a unique regime that is not typically encountered at lower frequencies. This effect is even more pronounced as the slot width increases to a point where the sides of the slot act as secondary leaking structures, and the well-known frequency–angle relationship is not obeyed as the energy at a given frequency is radiated in a broad range of angles. Therefore, to exploit the phase matching condition, which couples frequency to emission angle, one must use very thin rectangular slots d≪λ, at the expense of device efficiency. To address this problem, we explore an alternate slot aperture design, in which the slot width increases linearly along its length (i.e., a trapezoidal shape). We show that this preserves the phase-matching constraint while allowing higher output coupling efficiencies. Moreover, since a wider effective aperture is used, the radiated beam is narrow in both angular directions, allowing the generation of true pencil-like THz beams.

Integrated Intelligent Electromagnetic Radiator Design for Future THz Communication: A Review

“…In the second section, THz localization is discussed as the step before THz beamforming, which becomes increasingly important at high frequencies due to the high directivity utilized. A spectrum‐space method is presented as a potential solution that utilizes broadband leaky‐wave antennas with frequency‐dependent radiation patterns for one‐shot localization [ 59 ] . Finally, THz beamforming is elaborated.…”

“…As mentioned previously, beamforming can also be realized through a transmissive or reflective beamforming surface that palliates the stringent area constraint by separate the power generation and beamforming components. Venkatesh et al presented a reconfigurable metasurface that can be viewed as a pioneering attempt in realizing metasurface beamforming at THz frequencies [57,58] . As shown in Fig.…”

Jamming a terahertz wireless link

“…Terahertz waves (100 GHz to 10 THz) are considered a likely candidate for future generations of wireless technology 1 , 2 , due to the promise of large bandwidths and high data rates 3 – 5 . Unlike conventional radio frequency (RF) broadcasts, THz links rely on the use of highly directional beams generated from high-gain antennas designed to overcome the large free-space path loss 6 , 7 . This has the potential to make THz communication links more secure by restricting the ability of eavesdroppers to intercept narrow beams 8 – 14 .…”

The effect of angular dispersion on THz data transmission

“…Subsequently, we consider a leaky-wave antenna (LWA), which also exhibits a large angular dispersion. Indeed, in recent work by us and others, this angular dispersion has been directly exploited for valuable network functions 15 , 21 – 26 . These earlier studies have so far not considered the implications on link quality of employing strong angular dispersion for broadband data transmissions.…”