The THz spectrum is being explored due to its inherent large bandwidth to fulfill the throughput requirements for future wireless systems. However, there are intrinsic challenges for the exploitation of this spectrum for wireless communications, particularly concerning current technological capabilities. Moreover, it remains a big question if THz systems can be made efficient. In this contribution, we present a system analysis to show the potential of overcoming these challenges using quasi-optical antennas integrated with wideband SiGe-BiCMOS electronics and a suitable baseband design that can lead to the Tbit/sec and energy-efficient wireless transmission.

Radiative near-field links have gained noticeable interests recently for high-data-rate wireless communication. Unlike far-field links, near-field links can have negligible path loss within hundreds of meters for electrically large antennas at high frequencies. In this work, we propose a multi-lens quasi-optical (QO) system for 100-m near-field backhaul communication at H-band. The QO system is designed with compact size (aspect ratio of 1.3:1) and high coupling efficiency of 82%. Moreover, the rotation of an auxiliary lens realizes beam scanning for the link alignment. The scan range is in the order of 1 m with less than 2 dB scanning coupling loss and scanning magnification of 14.5:1.

This work presents a multi lens Quasi-Optical (QO) antenna for energy efficient backhaul/fronthaul links at 300GHz. By operating in the radiative near-field region, the proposed antenna system achieves power spreading loss of only 1dB for a point-to-point (PtP) link of 100m. The simulated antenna directivity is 62dBi and the half-power beamwidth is 0.15 degrees. To satisfy the tight alignment requirements of the envisioned scenario, scanning capability is included through the rotation of a lightweight free-standing silicon (Si) lens. This allows correction for misalignment of ± 2 degrees (or ± 13 beams) with a penalty of 1.8dB in the link’s performance.

This contribution presents the measurement strategy to accurately characterize probe-fed high-gain antennas operating in the sub-THz band. First, a near-field technique employing a quasi-optical system is introduced to enable characterization of backside radiating antennas (with respect to the landing pads). The proposed setup employs classical manipulators for probe landing (i.e., above the structure) and linear xyz CNC controlled translation stage. After, the calibration and modelling techniques to allow for an accurate input reflection-coefficient at the antenna input plane, and the estimation of the antenna gain, in a near field planar scanning system, are described in details. The experimental data of an high-gain backside-radiating lens antenna operating in D-band are presented to validate the proposed approach and characterization bench.