Performance Enhancement of a Si Hemispherical Lens Using a Coating Layer for 300 GHz Frequency Band

To enhance the radiation characteristics of an onchip antenna, in this paper, a silicon (Si) extended hemispherical dielectric lens antenna is designed with a coating layer for subterahertz (sub-THz) applications. First, to prove the concept, the coated Si lens is illuminated using a dielectric-filled WR-3.4 waveguide. From the simulations, it is observed that the designed coated lens offers better radiation characteristics compared to a non-coated lens in the frequency range of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$220-330 \text{GHz}$</tex>. In the second phase, an on-chip antenna is used for the lens illumination, which is designed on a high-permittivity silicon germanium (SiGe) dielectric substrate. The results show that the coated Si lens improves impedance matching and radiation performance of the on-chip antenna across the operating band, i.e., <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$230-360 \text{GHz}$</tex>.