Design, Uncertainty Analysis and Measurement of a Silicon-based Platelet THz Corrugated Horn

TL;DR

This paper presents the design, fabrication, and uncertainty analysis of a wideband silicon-based platelet corrugated horn operating at 170-320 GHz, introducing a novel method for axial misalignment analysis and its impact on performance.

Contribution

It introduces a universal mode matching method for axial misalignment analysis and quantitatively evaluates fabrication uncertainties in THz corrugated horns.

Findings

The horn achieves low sidelobe levels (<-30 dB) across the band.

Axial misalignment significantly degrades cross-polarization performance.

The proposed method accurately predicts fabrication tolerances for THz horns.

Abstract

Platelets corrugated horn is a promising technology for their scalability to a large corrugated horn array. In this paper, we present the design, fabrication, measurement and uncertainty analysis of a wideband 170-320 GHz platelet corrugated horn that features with low sidelobe across the band (<-30 dB). We also propose an accurate and universal method to analyze the axial misalignment of the platelets for the first time. It is based on the mode matching (MM) method with a closed-form solution to off-axis circular waveguide discontinuities obtained by using Graf addition theorem for the Bessel functions. The uncertainties introduced in the fabrication have been quantitatively analyzed using the Monte Carlo method. The analysis shows the cross-polarization of the corrugated horn degrades significantly with the axial misalignment. It well explains the discrepancy between the designed and the measured cross-polarization of platelets corrugated horn fabricated in THz band. The method can be used to determine the fabrication tolerance needed for other THz corrugated horns and evaluate the impact of the corrugated horn for astronomical observations.