Design and Characterization of a Low-Permittivity Lens for Sub-THz Applications

This paper presents the design of a low-permittivity (LP) extended hemispherical lens antenna with dual-layer matching sections for sub-terahertz (sub-THz) applications at 220-330 GHz. The matching layers between the source and the lens work as quarter-wavelength transformers whose main role is to provide a smooth transition from high to low permittivity. A rectangular waveguide feed is used to illuminate the lens. The analysis is done by attaching the waveguide to the lens surface and by introducing an air gap between them. The results show that this air gap improves impedance matching and radiation performance across the operating band.