An f/0.27 High-Gain Lens-Antenna for Ultra-Small Platforms at THz Frequencies

The development of a low focal number and low mass lens antenna is presented that enables Terahertz (THz) spectroscopy applications on ultra-compact platforms. The antenna operates efficiently over a 20% fractional bandwidth, from 450 GHz to 550 GHz, with a gain of 50 dBi at 500 GHz. The antenna consists of a hyperbolic silicon lens that is placed in a record low focal number configuration (f/# = 0.27) with respect to an advanced waveguide feed. An incident field-matching analysis is applied to investigate the optimal feed radiation pattern that maximizes the lens aperture efficiency, which would result in a 20% increase in aperture efficiency (>80%) with respect to a standard open ended waveguide (<60% aperture efficiency). A multi-layer leaky-wave (LW) stratification is quasi-analytically optimized to approximate the optimal feeding pattern, resulting in a > 70% lens aperture efficiency. An example LW stratification is synthesized using silicon micro-machining technology and is fully characterized in combination with the dielectric lens.