(Optica, 2022) Haddad, Thomas; Biurrun Quel, Carlos; Lu, Peng; Tebart, Jonas; Sievert, Benedikt; Makhlouf, Sumer; Grzeslo, Marcel; Teniente Vallinas, Jorge; Río Bocio, Carlos del; Stöhr, Andreas; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
A novel photonic-assisted 2-D Terahertz beam steering chip using only two tuning
elements is presented. The chip is based on an array of three leaky wave antennas (LWAs) with
a monolithically integrated beamforming network (BFN) on a 50 µm-thick indium phosphide
substrate. The THz beam angle in elevation (E-plane) is controlled via optical frequency tuning
using a tunable dual-wavelength laser. An optical delay line is used for azimuth (H-plane) beam
control. The simulated beam scanning range is 92° in elevation for a frequency sweep from
0.23 THz to 0.33 THz and 69.18° in azimuth for a time delay of 3.6 ps. For the frequency range
from 0.26 THz to 0.32 THz, it is confirmed experimentally that the THz beam scans from −12°
to +33°, which is in good agreement with the numerical simulations. The beam direction in
azimuth scans with a total angle of 39° when applying a delay difference of 1.68 ps. A good
agreement is found between theoretically predicted and experimentally determined THz beam
angles with a maximum angle deviation below 5°. The experimental scanning angles are limited
due to the mechanical constraints of the on-wafer probes, the on-chip integrated transition and
the bandwidth of the THz receiver LNA. The mechanical limitation will be overcome when using
a packaged chip.
