Study on the Effects of Aperture Dimensions on Shielding Effectiveness of the QTT Multi-Layer Shielding Structure

Multi-layer shielding effectively suppresses radiated emissions from electronic equipment near the telescope focal point, where electromagnetic leakage through apertures is the primary factor limiting shielding effectiveness (SE). Investigating aperture leakage impacts on overall shielding performance provides critical technical support for multi-layer shield design. To address the electromagnetic protection requirements for equipment near the focal region of the QiTai radio telescope (QTT), this study validates the accuracy and frequency adaptability of Robinson's theory and the Baum-Liu-Tesche (BLT) equation in calculating multi-layer shield aperture leakage. Statistically permissible aperture dimensions satisfying shielding requirement (SR) were determined for the 0.3--1.5 GHz band using these methods. Finite Integral Technique (FIT) simulations further quantified compliant aperture dimensions for the 1.5--6 GHz band, demonstrating that rectangular apertures of 3 mm × 3 mm or 4 mm × 1 mm, or circular apertures with diameters ≤ 3.3 mm, meet the QTT multi-layer shielding requirement.