Planar air-filled terahertz antenna array based on channelized coplanar waveguide using hierarchical silicon bulk micromachining

A planar air-filled terahertz antenna array based on channelized coplanar waveguide (CCPW) is proposed and fabricated using silicon bulk micromachining technology. Planar air-filled four-unit array composed of two silicon layers is verified at 300 GHz. Periodical field blocking stubs are loaded in the gaps of the CCPW alternatively to break the fringing field symmetry, generating an in-phase radiating aperture. The fabrication technology has two features: first, the silicon dielectrics are completely plated with gold, generating a purely air-filled antenna with high performance and second, the hierarchical micromachining method enables a single silicon layer to be divided into two sublayers, resulting in reduced antenna layers. The numerical result shows a simulated -10 dB impedance bandwidth of 71.1 GHz (25.95%, 238.4-309.5 GHz) and stable fan-shaped beams with broadside gains and radiation efficiencies higher than 10.6 dBi and 87.9%, respectively. Experiment of the fabricated prototype exhibits a bandwidth that totally covers the simulation and stable beams with broadside gains higher than 8.6 dBi. To the best of author's knowledge, this is the first time that a planar air-filled terahertz antenna array is proposed. Moreover, confirmation of the strategy demonstrates the antenna's distinguished suitability to realize antenna-in-package solution.