All-Silicon Planar Parabolic Reflector Antenna for Terahertz Applications

The development of practical terahertz systems requires high-gain, broadband and robust integrated antennas. In recent years, many photonics-inspired all-dielectric components have been demonstrated, however practical implementation of existing devices usually relies on perforated structures that can be fragile and exhibit cutoffs related to their gratings. In this paper, we present a novel, all-dielectric planar antenna that avoids perforations entirely. The antenna employs a dielectric slab parabolic reflector that collimates incident waves towards radiating rods, producing a fan-shaped beam. A thorough investigation of the optimal guided-wave collimating structure is presented utilizing geometric optics, along with a proof of concept for its use as a beam launcher in integrated terahertz circuits. Thereafter, the device is adapted as an antenna. The novel antenna, 19.83 mm × 20.97 mm in footprint and 200 µm thick, is broadband, lowprofile, readily integrable with planar, on-chip components, and exhibits a nearly-flat gain across the 220-330 GHz range, with a maximum value of 21.5 dBi. Input reflection coefficient is below-20 dB across the entire range, indicating excellent 40% fractional bandwidth, and a sidelobe level reaching as low as-28.4 dB for the E-plane and-39.5 dB for the H-plane.