Lens or resonator? - Electromagnetic behavior of an extended hemielliptic lens for a sub-mm wave receiver

TL;DR

This study uses full-wave numerical analysis to investigate the electromagnetic behavior of an extended hemielliptic silicon lens at sub-mm wave frequencies, revealing resonances that impact lens design for THz receivers.

Contribution

It introduces an efficient numerical method for analyzing the electromagnetic properties of extended hemielliptic lenses and uncovers resonance effects affecting lens focusability and design.

Findings

Resonances significantly influence lens focusability.

Rear-side extension alters the electromagnetic behavior.

Numerical method efficiently models lens scattering.

Abstract

The behavior of a 2-D model of an extended hemielliptic silicon lens of a size typical for THz applications is accurately studied for the case of a plane E-wave illumination. The full-wave analysis of the scattering problem is based on the Muller boundary integral equations that are uniquely solvable. Galerkin discretization scheme with a trigonometric basis leads to a very efficient numerical algorithm. Numerical results related to the focusability of the lens versus its rear-side extension and the angle of the plane-wave incidence, as well as near-field profiles, demonstrate strong resonances. Such effects can change the principles of optimal design of lens-based receivers.